Nuclear escalation is not a single ladder that automatically moves from conventional war to nuclear war. It is better understood as a series of decision points at which governments can either reinforce deterrence, attempt de-escalation, or take actions that increase the risk of further escalation. For Russia and NATO, the most dangerous pathway would involve a conventional confrontation becoming intertwined with nuclear signalling, heightened military readiness, attacks on critical systems, misinterpretation of warnings and increasingly compressed political decision-making. None of these steps makes nuclear use inevitable.
The scenarios discussed here are analytical possibilities, not predictions. Russia’s publicly stated nuclear policy defines circumstances in which Moscow says nuclear weapons could be used, while NATO maintains its own nuclear deterrence and political decision-making arrangements. But doctrine does not function as an automatic launch algorithm: actual escalation would depend on political decisions, battlefield developments, perceptions of threat, communication between governments and the choices made by multiple actors.
Escalation begins before nuclear weapons are used
The first stage of a nuclear crisis may look entirely conventional.
A confrontation could begin with a military incident, an attack on a state, a clash involving Russian and NATO forces, or a wider war in which one side believes its vital interests are increasingly threatened.
At this stage, nuclear weapons may remain instruments of deterrence rather than weapons being prepared for immediate employment.
The danger comes from the interaction between conventional military operations and nuclear signalling.
Russia has repeatedly incorporated nuclear messaging into its response to the Ukraine war, while NATO continues to describe nuclear weapons as part of its deterrence and defence posture. NATO’s current policy states that nuclear use against the Alliance would fundamentally alter the nature of a conflict, while emphasizing that circumstances in which NATO might use nuclear weapons are extremely remote.
That creates the first important distinction:
Nuclear deterrence can become more prominent during a conventional war without the conflict becoming a nuclear war.
A possible escalation pathway
The sequence below is one analytical scenario rather than a forecast.
| Stage | Possible development | What it could mean | What remains uncertain |
|---|---|---|---|
| 1 | Conventional confrontation | Military forces engage while nuclear weapons remain in the background | Whether either side views the conflict as existential |
| 2 | Nuclear signalling | Leaders issue warnings or alter nuclear readiness | Whether signalling is coercive, defensive, deterrent or intended for multiple audiences |
| 3 | Higher military readiness | Nuclear-capable forces or supporting systems become more active | Whether the change represents preparation for use or political signalling |
| 4 | Conventional attacks deepen | Strikes affect forces, territory or systems considered strategically important | How the targeted government interprets the attacks |
| 5 | Crisis decision-making compresses | Leaders have less time and greater uncertainty | Whether communication remains reliable |
| 6 | Nuclear threshold is approached | A government concludes that stated nuclear-use conditions may be relevant | Whether political leaders actually authorize nuclear employment |
| 7 | Limited nuclear use becomes a possibility | A nuclear weapon could be employed in a conflict | Whether the other side treats it as an isolated act or the beginning of a wider campaign |
| 8 | Post-use escalation or containment | Adversaries could retaliate, impose costs, pause or seek negotiations | The most consequential decisions would depend on circumstances that cannot be predicted in advance |
The value of such a framework is not that it predicts the future. It shows where miscalculation and political choice could change the direction of a crisis.
Stage 1: A conventional conflict creates the nuclear backdrop
A nuclear crisis does not necessarily begin with a nuclear event.
It can begin with a conventional war involving nuclear-armed states or their allies.
Russia and NATO already maintain military forces, nuclear deterrents and command structures designed around the possibility of major conflict. NATO describes its deterrence posture as a combination of nuclear, conventional and missile-defence capabilities, supplemented by space and cyber capabilities.
In a hypothetical Russia-NATO conflict, conventional operations could therefore take place under an existing nuclear shadow.
This is strategically important because both sides would have incentives to prevent the conventional conflict from crossing thresholds they consider intolerable.
But each side could interpret those thresholds differently.
That is where escalation risk begins.
Stage 2: Nuclear signalling enters the crisis
The next possible step would be nuclear signalling.
This could involve public statements, changes in military exercises, adjustments to readiness or other visible actions intended to communicate resolve.
Signalling does not necessarily mean that a government intends to use nuclear weapons.
It can serve several purposes simultaneously:
- deterrence;
- coercion;
- reassurance of allies;
- domestic political messaging;
- communicating perceived red lines;
- attempting to influence an adversary’s calculations.
Russia’s nuclear rhetoric during the war in Ukraine illustrates how nuclear signalling can accompany a conventional conflict without resulting in nuclear use. The Arms Control Association has documented repeated Russian nuclear warnings and exercises involving non-strategic nuclear capabilities since the full-scale invasion.
The analytical difficulty is that an adversary cannot directly observe intent.
A military movement may be preparation for an operation, a signalling measure, or both.
Stage 3: Nuclear forces could move to higher readiness
A more serious development would involve changes to nuclear readiness.
This is still not the same as authorization to use nuclear weapons.
In February 2022, Vladimir Putin ordered Russia’s nuclear forces to move to a “special regime of combat duty.” Arms Control Association analysis cited expert assessment that the measure brought nuclear systems into a working condition but did not itself demonstrate preparation for a first strike.
This distinction remains important.
Readiness is an indicator of preparedness, not proof of intent.
During a crisis, however, the adversary may not know exactly why readiness has increased.
That ambiguity can itself become destabilizing.
If Russia interprets NATO preparations as evidence that an attack is becoming more likely, it could increase its readiness further.
NATO could then interpret the Russian response as evidence of increasing nuclear danger.
A feedback loop becomes possible.
Stage 4: Conventional attacks begin affecting strategic interests
The risk could increase if conventional operations begin damaging assets that a nuclear-armed state regards as especially important.
These might include military command systems, strategic forces, early-warning infrastructure or other capabilities associated with national defence.
This does not mean that attacking such a system automatically causes nuclear escalation.
It means the political interpretation of the attack could become more consequential.
A conventional strike can have nuclear implications if leaders believe it threatens their ability to retaliate or command their forces.
This is sometimes described as the entanglement problem: conventional and nuclear systems can become sufficiently interconnected that actions intended to affect a conventional war are interpreted as threatening nuclear stability.
The problem becomes particularly acute when outside observers cannot distinguish between a country’s conventional military infrastructure and the systems supporting its nuclear forces.
Stage 5: Warning systems become increasingly important
As tensions rise, early-warning systems acquire greater strategic significance.
Nuclear powers maintain warning capabilities because their leaders need to determine whether an attack is occurring or likely to occur.
But warning systems are not infallible.
History includes episodes in which ambiguous information generated concern at the highest levels without resulting in nuclear use.
The famous 1995 Norwegian rocket incident is an example: a scientific rocket launched from Norway was initially detected by Russian warning systems in circumstances that led to activation of senior nuclear-command procedures before the launch was correctly identified. The episode ended without a nuclear response.
The broader lesson is not that a particular future system will fail.
It is that technical warning information still has to be interpreted by humans under pressure.
As a crisis becomes more intense, the consequences of misinterpreting ambiguous information can become more severe.
Stage 6: Political decision-making becomes compressed
One of the most dangerous characteristics of nuclear crises is time pressure.
Leaders may have incomplete information while believing that events are moving rapidly.
Military commanders may present multiple possibilities.
Intelligence assessments may disagree.
Communications with the adversary may become less reliable.
Political leaders may fear that waiting will reduce their options.
This creates a dangerous combination:
high stakes + uncertainty + limited time.
It does not guarantee nuclear escalation.
Indeed, nuclear command systems are designed partly to preserve decision-making under extreme conditions.
But the historical experience of nuclear crises shows why communication, verification and deliberate decision-making are central to risk reduction.
Stage 7: A government could interpret its nuclear-use conditions as relevant
This is the point at which doctrine becomes particularly important.
Russia’s revised nuclear policy, adopted in November 2024, describes circumstances in which nuclear weapons could be considered. Among other provisions, it identifies certain forms of conventional aggression that create a critical threat to Russia’s sovereignty or territorial integrity and describes circumstances involving attacks by nuclear or other weapons of mass destruction. It also incorporates Belarus into aspects of the nuclear deterrence framework.
These provisions should not be interpreted as automatic triggers.
A doctrinal condition can establish when nuclear use is permitted or contemplated within stated policy without establishing that nuclear use must follow.
The distinction is crucial.
For a detailed examination of Russia’s stated thresholds, see What Would Trigger Russia to Use Nuclear Weapons? Inside the Stated Conditions and Thresholds.
Stage 8: The adversary tries to determine whether the threshold has actually been crossed
Suppose Russia believed a conflict had reached a point covered by its nuclear policy.
The other side would still face uncertainty.
It might not know:
- how Russian leaders were interpreting the situation;
- whether the threshold was considered crossed;
- whether nuclear forces had actually been ordered into a new posture;
- whether public warnings were intended as deterrence;
- whether diplomatic channels remained available.
This uncertainty creates an information problem.
A government attempting to deter nuclear use could accidentally send signals that the other side interprets as preparation for escalation.
Conversely, excessive caution could be interpreted as weakness.
The challenge is therefore not simply military.
It is strategic communication under uncertainty.
Stage 9: A limited nuclear use becomes a possibility—not an inevitability
The most consequential hypothetical step would be actual nuclear employment.
This article does not treat a particular target, weapon type or attack sequence as a prediction.
The important analytical question is what happens politically once the nuclear threshold has been crossed.
NATO states explicitly that nuclear use against the Alliance would fundamentally alter the nature of a conflict. NATO also states that its nuclear decision-making remains under political control and that the circumstances in which it might use nuclear weapons are extremely remote.
A Russian nuclear strike would therefore not exist in isolation.
It would confront the United States, NATO governments and other states with a fundamentally different strategic environment.
The response could involve military, diplomatic, economic and conventional measures.
Which combination would actually be selected would depend on the circumstances and political decisions at the time.
Stage 10: The central danger becomes the interpretation of the first nuclear use
After a nuclear detonation, the most important question would not necessarily be what happened physically.
It would be:
What does the other side believe will happen next?
One government might interpret a nuclear strike as a limited coercive action intended to force negotiations.
Another might interpret it as the beginning of a larger campaign.
If the second interpretation dominates, preparations for further conflict could accelerate.
That creates a fundamental escalation problem.
The first nuclear use does not mechanically determine the next step.
It changes the decision environment in which the next step is taken.
Possible pathway A: Containment
One possible outcome is that nuclear use remains limited and the adversaries attempt to prevent further escalation.
This could involve diplomatic contacts, indirect communication, military deconfliction and efforts to establish that neither side intends to expand nuclear operations.
Such a pathway would depend on governments retaining control over their forces and maintaining enough communication to interpret each other’s actions.
It would also require political leaders to distinguish retaliation, deterrence and escalation.
This is a possibility, not a forecast.
There is no established rule stating that a limited nuclear exchange must remain limited.
Possible pathway B: Conventional retaliation
Another possibility would be a major conventional response rather than immediate nuclear retaliation.
NATO’s current policy emphasizes a broad mix of conventional, nuclear and missile-defence capabilities and states that any nuclear employment against NATO would fundamentally change the nature of the conflict.
That leaves substantial room for political decision-making.
A response could theoretically be designed to impose military or political costs while attempting to avoid further nuclear escalation.
The exact form such a response might take cannot responsibly be presented as predetermined.
Possible pathway C: Nuclear retaliation
A nuclear response is another possibility in a hypothetical scenario, but its likelihood cannot be predicted from doctrine alone.
Nuclear powers maintain forces partly because they want adversaries to believe that nuclear aggression could generate unacceptable consequences.
But deterrence depends on the adversary’s interpretation.
A government might conclude that nuclear retaliation is necessary.
It might instead conclude that a conventional response better serves its objectives.
Or it might prioritize preventing a second nuclear attack through diplomacy and crisis management.
The decision would be political and strategic rather than mechanically dictated by the first detonation.
Possible pathway D: A wider strategic exchange
The most severe pathway would involve further escalation from limited nuclear use toward attacks involving strategic nuclear forces.
This is the scenario that nuclear deterrence seeks to prevent.
Once strategic forces are placed under extreme pressure, the consequences can become global.
The Arms Control Association’s discussion of the Princeton “Plan A” simulation illustrates one plausible pathway in which a conflict beginning in Europe escalates through successive nuclear exchanges into a much larger catastrophe. The authors explicitly present it as a plausible scenario rather than a prediction.
That distinction is essential.
Scenario modelling demonstrates how escalation could occur.
It does not demonstrate that it will occur.
Why escalation is not necessarily linear
The word “escalation” can imply a staircase.
Real crises are less orderly.
A conflict could move forward and backward.
Governments could raise readiness and then reduce it.
A military incident could produce an intense diplomatic response without further military escalation.
A nuclear warning could be followed by negotiations.
A conventional battlefield setback could produce restraint rather than escalation.
The most useful model is therefore not:
Step 1 → Step 2 → Step 3 → Nuclear war.
It is:
Crisis → decision point → response → adversary interpretation → new decision point.
Every decision changes the information available to the other side.
Miscalculation can be more important than deliberate escalation
Not every dangerous escalation would necessarily result from a government deliberately choosing a larger war.
Miscalculation can produce the same outcome.
One side may believe an action is limited.
The other may perceive it as preparation for a larger attack.
A military exercise may be interpreted as operational preparation.
A defensive deployment may be interpreted as an offensive threat.
A cyberattack intended to disrupt conventional military systems could be interpreted as an attempt to blind nuclear command-and-control.
This is why nuclear stability depends not only on weapons and doctrines but also on predictability and communication.
Cyber and space systems complicate the picture
Modern military operations increasingly depend on digital communications, satellites, sensors and networked command systems.
That creates new escalation problems.
An attack against a dual-use satellite, communications network or command infrastructure could have both conventional and nuclear implications.
The attacker might intend to affect a conventional military capability.
The target country might fear that its nuclear deterrent is being compromised.
That perception could create pressure to act before the perceived vulnerability becomes worse.
This does not mean cyber or space attacks automatically produce nuclear escalation.
It means that the distinction between conventional and nuclear infrastructure can become harder to maintain.
For broader context on how interconnected digital systems can create new security risks, see AI Security’s New Front Line: What Happens When an AI Agent Can Touch Your Systems?. The relevant lesson here is narrower: systems that perform multiple functions can create uncertainty about the consequences of attacking them.
NATO’s response would not be controlled by a single automatic mechanism
A Russian nuclear strike against a NATO member would create an unprecedented political crisis for the Alliance.
But NATO does not operate under a public rule saying that a particular type of Russian nuclear attack automatically produces a particular nuclear response.
NATO’s nuclear policy is politically controlled.
The Nuclear Planning Group is the Alliance’s senior body for nuclear deterrence consultation and decision-making, while NATO’s broader political leadership establishes the strategic direction. France does not participate in the NPG, reflecting its separate nuclear decision-making arrangements.
The existence of multiple decision-making centres is itself part of NATO’s deterrence structure.
The United States, United Kingdom and France maintain independent nuclear forces and separate national decision-making authorities.
That makes the alliance’s response more complex than a simple “button-for-button” model.
The role of diplomacy becomes more important after nuclear use
Paradoxically, diplomacy could become more important after the nuclear threshold had been crossed.
Once nuclear weapons have been used, governments would have powerful incentives to establish communication and clarify intentions.
Potential objectives could include:
- preventing additional nuclear use;
- protecting civilians;
- establishing military deconfliction;
- communicating red lines;
- creating channels for negotiations;
- preventing accidental escalation;
- addressing wider international security consequences.
This would not eliminate military responses.
It would mean that military and diplomatic activity could occur simultaneously.
For a broader examination of how governments and international institutions might respond to an actual Russian nuclear strike, see What Would the International Response to a Russian Nuclear Strike Look Like?.
Alliances can both restrain and complicate escalation
Alliances create an important dilemma.
A credible alliance commitment can deter attacks by making clear that aggression against one member could produce a collective response.
But an attack on one member can also create pressure on the alliance to demonstrate that its commitments are credible.
NATO explicitly describes collective defence and nuclear deterrence as interconnected parts of its security posture.
This means an attack involving one country can rapidly become a multinational political crisis.
At the same time, consultation provides an opportunity for allies to coordinate their response and reduce the risk that individual national actions unintentionally produce uncontrolled escalation.
Why the first nuclear use would be so difficult to interpret
Consider three possible interpretations of the same event.
Interpretation one: Russia uses a nuclear weapon to signal that it wants the conflict to stop.
Interpretation two: Russia uses it as the opening move in a broader escalation campaign.
Interpretation three: Russian leaders believe they are responding defensively to an existential threat.
The physical event could be identical.
The strategic implications would be very different.
The problem is that the opposing government cannot directly observe the first government’s internal reasoning.
It must infer intent from statements, force movements, communications and subsequent actions.
That is why nuclear escalation is fundamentally an information problem as well as a military problem.
Why Russia’s doctrine matters—but does not settle the outcome
Russia’s nuclear doctrine provides useful information about officially stated conditions.
It does not tell outsiders exactly how leaders would interpret every future crisis.
Doctrines are political documents.
Their language can be deliberately broad.
They can evolve.
They can be accompanied by signalling intended to influence an adversary.
And actual decisions depend on circumstances that cannot be fully specified in advance.
The 2024 revision therefore matters as evidence of Russia’s declared policy, but it should not be treated as a prediction of Russian behaviour in every hypothetical conflict.
Why NATO’s doctrine also matters
The same analytical caution applies to NATO.
NATO publicly describes nuclear use as extremely remote and emphasizes deterrence rather than battlefield employment. Its current policy nevertheless maintains nuclear capabilities and political arrangements intended to preserve the credibility of the Alliance’s deterrent.
Therefore, two propositions can simultaneously be true:
- NATO seeks to deter nuclear attack and considers nuclear use extremely remote.
- NATO maintains nuclear forces because it wants potential adversaries to believe that nuclear aggression could produce severe consequences.
That is the logic of deterrence.
The purpose is to make the feared event less likely by establishing consequences before it happens.
The escalation ladder has off-ramps
An important feature often lost in dramatic nuclear scenarios is the existence of possible off-ramps.
At almost every stage, governments can choose measures that reduce rather than increase escalation.
These can include:
- direct diplomatic communication;
- military-to-military contacts;
- public clarification of intentions;
- suspension or modification of provocative exercises;
- reciprocal reductions in readiness;
- negotiated pauses;
- third-party diplomacy;
- arms-control discussions;
- humanitarian arrangements.
None guarantees success.
But the existence of off-ramps means escalation is not mechanically predetermined.
A crisis can become more dangerous without becoming nuclear.
It can also move from severe confrontation toward stabilization.
The most dangerous combination is ambiguity plus speed
The greatest risk does not necessarily come from any single weapon.
It can arise when several conditions occur together:
ambiguous intentions, high military readiness, vulnerable communications, rapidly changing battlefield conditions and pressure for immediate decisions.
Each condition increases uncertainty.
Together, they can create a situation in which leaders make decisions based partly on what they fear the other side might do.
That is the classic logic of inadvertent escalation.
A nuclear crisis could also stop before nuclear use
It is important not to overlook the most common outcome of deterrence: the feared action does not happen.
A government can issue nuclear threats without using nuclear weapons.
A military can raise readiness without launching.
An adversary can respond with conventional measures and diplomacy.
Leaders can decide that the risks of crossing the nuclear threshold outweigh the potential benefits.
The fact that a scenario is technically possible does not establish that it is probable.
That distinction is especially important in public discussions of nuclear weapons, where hypothetical chains are sometimes presented as though they were forecasts.
What would make a scenario more concerning?
No single development can reliably establish that nuclear war is imminent.
But analysts generally pay close attention to combinations of developments.
Particularly significant would be:
- explicit changes in nuclear-use policy;
- unusual changes in nuclear-force readiness;
- movement or preparation of nuclear-capable forces;
- severe disruption of strategic communications;
- attacks affecting early-warning systems;
- direct clashes between nuclear-armed states;
- breakdown of crisis communication;
- public statements indicating that leaders perceive an existential threat.
Even then, interpretation requires context.
NATO itself continues to emphasize the importance of nuclear consultation, political control and credible deterrence while simultaneously describing nuclear employment as extremely remote.
What would make the situation less dangerous?
The opposite indicators would include restored communication, reduced military alert levels, cancellation or modification of unusual exercises, clearer public statements about intentions and renewed diplomatic engagement.
Again, none is conclusive.
The purpose of watching such indicators is to understand whether governments are creating more or fewer opportunities for controlled decision-making.
The difference between nuclear signalling and nuclear employment
This distinction deserves particular emphasis.
A government can use nuclear weapons rhetorically without using them militarily.
It can increase readiness without launching.
It can conduct an exercise without beginning an attack.
It can revise doctrine without changing its immediate operational posture.
These are different events.
Treating them as interchangeable produces a distorted picture of nuclear risk.
The Arms Control Association’s analysis of Russia’s 2022 nuclear alert, for example, explicitly distinguished increased readiness from evidence that Russia was preparing to launch a first strike.
Why “tactical” nuclear use would not necessarily remain tactical
One of the most important uncertainties concerns what happens after a limited nuclear strike.
The word “limited” describes the initial scale of an action.
It does not guarantee a limited political response.
A nuclear attack could alter an adversary’s perception of the entire conflict.
NATO states that any employment of nuclear weapons against the Alliance would fundamentally alter the nature of the conflict.
That is why analysts distinguish between the size of an initial nuclear action and the potential scale of the resulting escalation.
A small initial event can create very large strategic consequences.
Why escalation modelling has limits
Scenario models are useful because they force analysts to examine sequences rather than isolated events.
But models depend on assumptions.
They must specify:
- who acts first;
- how governments interpret events;
- what military options are available;
- how leaders respond;
- whether communication survives;
- whether escalation is deliberate or accidental.
Change one assumption and the outcome can change dramatically.
The Princeton “Plan A” model, for example, illustrates one plausible escalation pathway rather than claiming that nuclear war would necessarily follow that exact sequence.
That is how scenario analysis should be read.
It identifies possible mechanisms of escalation, not a predetermined future.
The nuclear threshold is ultimately political
Weapons create capabilities.
Doctrine establishes stated conditions.
Command systems provide the means to transmit decisions.
But escalation ultimately depends on human decisions.
A government can decide not to cross a threshold.
It can seek negotiations.
It can interpret an attack as less severe than an adversary expected.
It can decide that a conventional response is sufficient.
Or it can reach the opposite conclusion.
This makes nuclear escalation fundamentally different from a purely mechanical process.
The most important uncertainty comes after the first major escalation signal
The central question in a nuclear crisis is not simply whether one side possesses nuclear weapons.
That is already known.
The more difficult question is whether leaders can maintain control over the crisis as military pressure increases.
If communication remains open, governments may have opportunities to clarify intentions and create off-ramps.
If communication collapses while military readiness increases, uncertainty grows.
If both sides begin making decisions based on worst-case assumptions about the other’s intentions, the room for compromise can narrow.
That is where deterrence can become unstable.
What the next stage would depend on
A Russia-NATO nuclear crisis would therefore not have one predetermined pathway.
It could stop at conventional confrontation.
It could involve nuclear signalling without nuclear use.
It could produce heightened readiness followed by de-escalation.
It could cross the nuclear threshold and then return to diplomacy.
Or, under much more dangerous circumstances, it could escalate into a broader nuclear conflict.
The evidence does not permit assigning a reliable probability to each hypothetical pathway.
What can be assessed is the mechanism connecting them.
The crucial transition is not from one weapon to another. It is from one interpretation of an adversary’s actions to another.
A conventional attack may be interpreted as battlefield action.
The same attack may later be interpreted as an existential threat.
A nuclear warning may be interpreted as deterrence.
It may instead be interpreted as preparation for attack.
A limited nuclear strike may be intended to coerce.
It may be interpreted as the opening of a larger offensive.
Those interpretations shape the decisions that follow.
The key question is whether escalation can be controlled
Nuclear escalation should therefore be understood as a branching decision process rather than a fixed ladder.
Russia’s stated nuclear policy provides information about the circumstances Moscow says could justify nuclear use. NATO maintains its own nuclear deterrence system and political decision-making arrangements. Neither framework establishes a deterministic sequence in which a particular conventional event automatically produces nuclear war.
The most consequential variables would be the perceptions of political leaders, the reliability of warning and communications systems, the behaviour of military forces, the credibility of deterrent signals and the availability of diplomatic off-ramps.
That is why the study of nuclear escalation is ultimately a study of decision-making under extreme uncertainty.
The danger lies not only in a government deliberately deciding to escalate, but also in circumstances where each side begins reacting to what it believes the other side might do next. Once that cycle takes hold, the space for controlled choices can shrink quickly. The central strategic objective of nuclear deterrence is therefore not to make escalation manageable after nuclear war begins; it is to prevent the crisis from reaching the point where leaders face those choices at all.
For the broader strategic context, Inside Russia’s Nuclear Doctrine: From Deterrence to Escalation examines the evolution of Russia’s nuclear policy, while What Would the International Response to a Russian Nuclear Strike Look Like? considers what could follow if the nuclear threshold were actually crossed.