Nuclear Darkness

New Terms for a Common Understanding of De-Alerting:

Launch Before or After Nuclear Detonation

by Steven Starr, PSR, University of Missouri

The discussion of de-alerting has been complicated by the absence of a common understanding and description of how the United States and the Russian Federation might employ their nuclear arsenals during the initial phases of a nuclear exchange. A resulting lack of universally agreed terminology has hindered diplomatic efforts to lower the operational status of nuclear forces and thus reduce the possibility of accidental, unauthorized or inadvertent use of nuclear weapons.

The recent authoritative report, Reframing Nuclear De-Alert (published by the EastWest Institute and sponsored by the governments of Switzerland and New Zealand), makes it clear that differences in language and translation, combined with military secrecy, have created a confusion of definitions and terms even among experts.1 Thus the report states that its first objective, ". . . is to define the issue to reconcile differing views of the de-alert concept that may themselves hinder attempts to reduce the readiness of nuclear weapons."

Reframing Nuclear De-Alert identifies the terms, "Otvetno-Vstrechnyi Udar" (OVU), "Launch Under Attack" (LUA) and "Launch On Warning" (LOW) as those most frequently used in English and Russian literature on de-alerting.  The report and its references list the varying and even opposing definitions commonly used for LOW and LUA, and demonstrates that such variation in meanings must be reconciled in order to move beyond semantic debate.3

One solution to this problem is to create new, agreed terminology, which would reduce ambiguity (and thus disagreement) when describing how the U.S. and Russia might respond to a perceived or confirmed nuclear attack. This can be accomplished by identifying and utilizing common components of two official U.S. and Russian military definitions (LUA and OVU) which describe the initiation of a retaliatory nuclear strike in response to a first nuclear attack.

Reframing Nuclear De-Alert provides both these definitions. The first comes from the U.S. Department of Defense online military dictionary listing for LUA: "Execution by the President of the Single Integrated Operational Plan forces subsequent to tactical warning of strategic nuclear attack against the United States and prior to first impact" [emphasis added].4 The Russian Federation’s Strategic Rocket Forces (SRF) also describes the initiation of a retaliatory nuclear strike in response to a (perceived) first nuclear attack. The SRF defines OVU as "a form of responsive measures of Strategic Nuclear Forces ordered after analysis of all reconnaissance and early warning data so that the transmitting of launch orders to a major portion of delivery systems and the launch of those systems are carried out before the first impact" [emphasis added].5

Note that both military definitions specify that the launch of strategic nuclear forces occurs prior to or before the attack is confirmed by "first impact".  The term "first impact" in these definitions means the impact and detonation of one or more nuclear warheads.

Thus the U.S. and Russian military appear to recognize that nuclear detonation is the pivotal event which drives the launch process. Most importantly, only nuclear detonation provides unequivocal proof that a nuclear attack (and not a false warning or conventional attack) has actually occurred. Early Warning Systems (EWS) cannot discriminate between conventional and nuclear warheads while they are still in flight; only the detonation of the perceived warheads will reveal if they are conventional or nuclear – or if they exist at all.

Without the final physical evidence provided by nuclear detonation, only the perception of the imminent "nuclear" attack exists. Before and until a nuclear detonation takes place, the decision to launch a nuclear strike must be based essentially upon electronic EWS data and other forms of technical and strategic information. Thus a nuclear strike launched before detonation is essentially responsive and preemptive in nature.6

In all these circumstances, the launch of a nuclear strike can be characterized on the basis of when it occurs – before or after the first nuclear detonation confirms that a perceived nuclear attack was indeed underway. This approach (1) allows an observer to simply describe the launch of a nuclear attack as a chain of observable physical events, and (2) separates the launch of nuclear forces into two general classes: Launch Before Nuclear Detonation and Launch After Nuclear Detonation.

Chronological classification of nuclear attack

Launch Before Nuclear Detonation (LBND or LBD*)

(Launched before first impact)

(a)Preemptive Launch: Unambiguous First Use of nuclear weaponry ordered in the absence of tactical warning of nuclear attack

(b) Responsive Launch Before Nuclear Detonation(RLBND or RLBD*): The launch of a nuclear strike in response to tactical warning of a nuclear attack, but before one or more nuclear detonations provide unequivocal proof that the attack is in fact nuclear.

Launch After Nuclear Detonation (LAND or LAD*)

(Launched after first impact)

*The word Nuclear and the corresponding letter N can both be omitted from these terms and acronyms once it is generally understood that Detonation refers to Nuclear Detonation

Launch Before Nuclear Detonation (LBND or LBD)7 includes two distinct categories of launch. Both are inherently preemptive and occur before the unequivocal proof of a hostile nuclear attack is obtained through nuclear detonation.

Preemptive Launch is the unambiguous First Use of nuclear weaponry. It is ordered in the absence of tactical warning of nuclear attack, although perhaps after a strategic warning of attack.8 There is no apparent disagreement about this term, but it is mentioned in order to clarify the sequence of events in relation to the other terms being defined.

Responsive Launch Before Nuclear Detonation (RLBND or RLBD) is the launch of a nuclear strike in response to tactical warning of an incoming nuclear attack, but before one or more nuclear detonations (precisely predicted by EWS data) provide unequivocal proof that the perceived attack is in fact a nuclear attack. RLBD does not imply that political or military leaders would utilize a responsive launch process. However, the capability to initiate a RLBD is a primary attribute and function of all operational high-alert nuclear weapons.

Although RLBD would not likely be intended as a Preemptive Launch, it would be made upon the presumption that an incoming nuclear attack was underway, but not upon confirmation of nuclear detonation. RLBD thus creates the appalling danger that a false warning of nuclear attack might be accepted as true and would trigger a "responsive" nuclear strike which in fact would be a first-strike. High-alert nuclear forces are what make a RBLD possible; de-alerting nuclear forces would preclude RLBD.9

RLBD could easily replace the term "Launch on Warning" (LOW). No official military definition exists for LOW, and so no effort would be required to edit or eliminate it from military texts. The absence of a formal definition for LOW has led to the impression that LOW implies an essentially reflexive nuclear launch will occur upon tactical warning of strategic attack (a fact hotly contested by many in the military). Thus there probably would be little official objection to the disappearance of LOW from the de-alerting discussion.10

Launch After NuclearDetonation(LAND or LAD) could be used to replace the term "Launch Under Attack". This proposal may at first seem counterintuitive, because the US DOD dictionary defines LUA as occurring "prior to first impact". However, Russian military experts have often used LUA to describe a launch which is carried out after the first nuclear detonation confirms an incoming first-strike.11 The current confusion between LUA definitions is a good enough reason in itself to discard LUA – since if consensus is to be reached, one of the LUA definitions must be eliminated.

LAD also follows logically from LBD. The universal adoption of a policy of launching only after one or more nuclear detonations have been confirmed would preclude the deadly mistake of launching a responsive or reflexive nuclear strike based upon a false warning.12 Because technical failure, human error and deliberate sabotage (and some combination of these circumstances) can all cause EWS and nuclear command and control systems to issue false warnings of attack, a launch based upon a false warning would cause an accidental nuclear war.13 Adopting a policy of LAD would also prevent the launch of nuclear weapons in reaction to an incoming strike of conventional warheads.14

The accidental, unauthorized and/or inadvertent launch of a nuclear weapon (or weapons) has previously been considered a "low probability event". New circumstances, however, have raised doubts about the validity of this calculation. For example, deliberate terrorist acts and the effects of cyberwarfare have become variables which make it impossible to calculate odds in this equation of ultimate risk.15 What is certain, however, is (1) maintaining large arsenals of strategic nuclear weapons at high alert makes it possible for these events to occur, and (2) the risk of such an occurrence is cumulative and that over time the odds increase that nuclear weapons will be used in conflict.16

Given that the consequences of an accidental launch or a single failure of deterrence could lead to apocalyptic consequences,17 it is imperative that the general de-alerting discussion should move forward without delay. It is time, therefore, to eliminate outdated and confusing terms that have already slowed the diplomatic process, and replace them with universally agreed terminology which will facilitate debate and mutual understanding.

More on war consequences

City on Fire

by Lynn Eden

The US military underestimates by a factor of 4 to 25 times the prompt damage likely to be caused by its nuclear weapons, because it does not estimate damage which would be created by nuclear firestorms.


  1. Reframing Nuclear De-Alert, East-West Institute, Swiss Confederation, New Zealand, 2009.
  2. Ibid, p.1.
  3. E. Miasnikov, General (Ret.) V. Esin, General (Ret.) V. Koltunov. "Comments on U.S. Discussion Papers: On Definitions in the Discussion of De-Alerting," Presented at EWI’s seminar Re-framing De-Alert: Decreasing the Operational Readiness of Nuclear Weapons Systems in the U.S.-Russia, June 21-23, 2009, in Yverdon-les-Bains,, Switzerland, and W. Slocombe, "De-alerting: Diagnoses, Prescriptions and Side Effects.", Presented at EWI’s seminar Re-framing De-Alert: Decreasing the Operational Readiness of Nuclear Weapons Systems in the U.S.-Russia Context. June 21-23, 2009, in Yverdon-les-Bains, Switzerland.

  5. E. Miasnikov, et al, "Comments on U.S. Discussion Papers . . .", op. cit., p. 3.
  6. A preemptive characterization corresponds to the description by a Russian expert of the previously noted SRF definition of OVU as a "retaliatory offensive strike", as described on page 2 of Reframing Nuclear De-Alert.
  7. The word Nuclear and the corresponding letter N can both be omitted from all the new terms and acronyms once it is generally understood that Detonation refers to Nuclear Detonation
  8. The U.S. DOD defines "strategic warning" as "A warning prior to the initiation of a threatening act" [emphasis added], see and also defines a "tactical warning" as "A warning after initiation of a threatening or hostile act based on an evaluation of information from all available sources." [emphasis added],
  9. The approximately 30 minute flight time of intercontinental ballistic missiles creates the compressed decision-making time that drives the responsive launch process; de-alerting nuclear forces so that they are unable to be launched in less than 30 minutes precludes a responsive launch.

  10. Reframing Nuclear De-Alert attempts to separate existing definitions of LOW based upon the idea that some versions of LOW depend upon a "strategic warning" while others rely upon a "tactical warning" of attack (p. 2). However, since all working definitions of LOW describe a situation after a launch has already been detected, this seems to be a point of confusion. Reframing Nuclear De-Alert also references a definition which states that LOW is ". . . an attack ordered and carried out after early-warning sensors indicate an incoming strike but before enemy missiles hit their targets" (p. 2). However, it is not "missiles" but rather (nuclear) warheads which arrive at their targets during a (nuclear) attack; this definition misses this essential point.  All these issues can quickly be resolved when the confirmation of nuclear detonation(s) becomes the defining aspect of deciding whether or not a nuclear attack has occurred.

  11. V. Yarynich, C3: Nuclear Command, Control, Cooperation, Washington, D.C., Center for Defense Information, 2003, pp. 28 -30. Colonel Yarynich (writing in English) uses LUA to mean the delivery of a retaliatory nuclear strike "in response to an actually delivered strike".
  12. A. Phillips, S. Starr, "Change Launch on Warning Policy", STAR (Strategic Arms Reduction) website of the Moscow Institute of Physics and Technology, and (Russian)
  13. A. Phillips, "20 Mishaps that Might Have Started Accidental Nuclear War", Nuclear Age Peace Foundation, January, 1998,  and B. Blair, "Increasing Warning and Decision Time (‘De-Alerting’), World Security Institute, International Conference on Nuclear Disarmament, Oslo February 26-27, 2008.
  14. A. Phillips, S. Starr, "Replace Launch on Warning Policy with Retaliatory Launch Only After Detonation (RLOAD)",  and
  15. Twenty nations, including North Korea, have developed dedicated computer attack programs which deploy viruses that are designed to disable, confuse and delay nuclear command and control systems, see A. Hebert, "Information Battleground", Air Force Magazine, Vol. 88, No. 12, December 2005.
  16. M. Hellman, "Risk Analysis of Nuclear Deterrence", The Bent of Tau Beta Pi. The Engineering Honor Society, Spring 2008,
  17. See