Launch on warning

Launch on warning (LOW) is a strategy of nuclear weapon retaliation that gained recognition during the Cold War between the United States and the Soviet Union. With the invention of intercontinental ballistic missiles (ICBMs), launch on warning became an integral part of mutually assured destruction (MAD) theory. Under this strategy, a retaliatory strike is launched upon warning of enemy nuclear attack, while its missiles are still in the air, and before detonation occurs.

History
Before the introduction of intercontinental ballistic missiles (ICBMs), the Strategic Air Command had multiple bombers on patrol at all times; so, presumably, did its Soviet counterpart. In the event of a nuclear strike by one of the nations, the other nation would order their bombers to fly to the other country and drop their nuclear payload on predetermined targets. In the United States, these bombers were typically either B-47 Stratojets or B-52 Stratofortresses, and there were three major flight routes. Keeping bombers in the air assured that a retaliatory strike would be feasible even if the initial strike were to impair ground facilities. At the height of the Cold War, the United States had special Boeing EC-135 "Looking Glass" aircraft equipped as control centers for the nuclear arsenal. The battle staff included a general or flag officer who was authorized to order a retaliatory strike in the event that the President could not be contacted.

Launch on warning has its roots in U.S. President Dwight Eisenhower's "Positive Control" strategy, but really took shape with the introduction of the Minuteman missile. Since many ICBMs (including the Minuteman) were launched from underground silos, the concern arose that a first strike by one nation could destroy the ground launch facilities of the retaliating nation.

'''Arms Control Today, November/December 1997 Clinton Issues New Guidelines on U.S. Nuclear Weapons Doctrine (PDD 60)'''

THE CLINTON administration quietly made a significant change in U.S. strategic nuclear doctrine in November by formally abandoning guidelines issued by the Reagan administration in 1981 that the United States must be prepared to fight and win a protracted nuclear war. The new presidential decision directive (PDD), details of which were first reported in The Washington Post on December 7, operates from the premise that the primary role of nuclear weapons in the post-Cold War era is deterrence. In a December 23 interview, Robert Bell, senior director for defense policy and arms control at the National Security Council, provided additional information about the PDD and clarified some misperceptions in the press with respect to the Clinton administration's policy on "launch on warning" and the use of nuclear weapons against a chemical or biological weapons attack.

New Guidelines

Due to its highly classified nature, many specific details about the PDD have not been made public. Nevertheless, Bell confirmed that "We have made an important change in terms of strategic nuclear doctrine in reorienting our presidential guidance away from any sense that you could fight and win a protracted nuclear war to a strategic posture that focuses on deterrence."

The administration made the decision to rewrite the old nuclear guidelines early in 1997. At that time, General John Shalikashvili, then-chairman of the Joint Chiefs of Staff, explained to President Clinton that the United States could not reduce its nuclear arsenal to the level that was being discussed for START III (2,000 to 2,500 deployed strategic warheads) and carry out the objectives of the 1981 nuclear guidelines. Bell pointed out that this assumed that the goals of the old guidelines could ever have been realized—a skepticism that has been voiced by former Reagan administration officials. Hence, one key factor influencing the administration's decision to rewrite the old guidelines was that they were not compatible with the U.S. objective of achieving further strategic force reductions with the Russians.

Moreover, the administration viewed the 1981 guidelines as an anachronism of the Cold War. The notion that the United States still had to be prepared to fight and win a protracted nuclear war today seemed out of touch with reality given the fact that it has been six years since the collapse of the Soviet Union. In this connection, Bell said the 1981 directive "reads like a document you would expect to have been written at the height of the Cold War, not something that you would want operative today...."

Launch on Warning

Bell said the press had incorrectly indicated that the PDD "still allows" the United States to launch nuclear weapons upon receiving warning of an attack. Bell emphasized that "there is no change in this PDD with respect to U.S. policy on launch on warning and that policy is that we do not, not rely on it." In fact, Bell said "in this PDD we direct our military forces to continue to posture themselves in such a way as to not rely on launch on warning--to be able to absorb a nuclear strike and still have enough force surviving to constitute credible deterrence."

Bell pointed out that while the United States has always had the "technical capability" to implement a policy of launch on warning, it has chosen not to do so. "Our policy is to confirm that we are under nuclear attack with actual detonations before retaliating," he said.

Negative Security Assurances

Bell also dispelled the published report that the PDD expands U.S. nuclear options against a chemical or biological weapons attack. "This PDD reaffirms explicitly, virtually verbatim, the policy of this administration as we stated it the last four or five years, including during the extension of the Non-Proliferation Treaty [NPT], the negotiation of the CTB [Comprehensive Test Ban] and the ratification of the Chemical Weapons Convention," he said.

Specifically, the PDD reaffirms the 1995 statement on negative security assurances issued by Secretary of State Warren Christopher on behalf of President Clinton at the time of the indefinite extension of the NPT. This statement reiterated in a slightly more restrictive form the 1978 statement on the non-use of nuclear weapons issued by Secretary of State Cyrus Vance on behalf of President Carter.

In this context, Bell explained that it is U.S. policy not to use nuclear weapons first against any state except in three cases. First, "if a state that we are engaged in conflict with is a nuclear-capable state, we do not necessarily intend to wait until that state uses nuclear weapons first--we reserve the right to use nuclear weapons first in a conflict whether its CW [chemical weapons], BW [biological weapons] or for that matter conventional [weapons]," he said. Under the second scenario, Bell said the United States reserves the right to use nuclear weapons first "if a state is not a state in good standing under the Non-Proliferation Treaty or an equivalent international convention." Finally, he said if a state attacks the United States, its allies or its forces "in alliance" with a nuclear-capable state, then the United States reserves the right to use nuclear weapons first, even if that state is not a nuclear-capable state and is in good standing under the NPT. Because these three exceptions have existed for some time, Bell said "there is no policy change whatsoever in this PDD with respect to fundamental U.S. position on no first use of nuclear weapons."

The introduction of nuclear-tipped ICBMs required new strategies because, unlike bombers, ICBMs cannot be recalled after launch. There were two primary options. One option, "retaliation after ride-out," required the second-strike nation to wait until after they were attacked to launch their missiles. Some portion of the nuclear arsenal would inevitably be destroyed in such an attack. This led to both superpowers investing heavily in survivable basing modes for their nuclear forces, including hardened underground missile silos for ICBMs, and submarine-launched ballistic missiles. The other choice was "launch on warning" - launching nuclear missiles before the other side's missiles could destroy them. This capability became possible primarily because of improvements in missile technology that allowed for faster launches, along with invention of the Ballistic Missile Early Warning System in the early 1960s, which made it possible for the U.S. to detect the launch of Soviet missiles. This capability was further enhanced in the 1970s with the deployment of space-based launch detection technology on both sides, the American geosynchronous DSP and Russian Oko satellites. Evidence found in declassified documents suggests that launch on warning was, at least in part, the policy of the United States from the late 1950s through to at least the 1970s.

Strategies are available that can reduce the effectiveness of a launch on warning stance. For example, the first-strike nation can use a technique called X-ray pin-down to delay a retaliatory response. This technique involves a barrage of submarine-based missiles fired from close range in a "depressed trajectory" mode that reaches its targets in minutes. The warheads would be set to explode every minute or so at high altitudes, which significantly disrupts the ability of the attacked nation to successfully launch its own ICBMs. Additionally, submarines could launch a depressed-trajectory strike against the capital of the targeted country, in an effort to destroy its command structure before any retaliatory decision could be made. This is known as a decapitation strike.

The deployment of submarine-launched ballistic missiles (SLBMs) decreases the strategic need for a launch on warning strategy. These submarines are capable of hiding in the ocean during an attack, thus ensuring that a second-strike can be made even if the attacked country is unable to launch a land-based counterstrike.