According to the theories of nuclear deterrence and mutual assured destruction, full
countervalue retaliation would be the likely fate for any state that unleashed a first strike. To maintain credible deterrence, nuclear-weapons states have taken measures to give their enemies reason to believe that a first strike would lead to unacceptable results. The main strategy relies on creating doubt among enemy strategists regarding nuclear capacity, weapons characteristics, facility and infrastructure vulnerability, early warning systems, intelligence penetration, strategic plans, and political will. In terms of military capabilities, the aim is to create the impression of the maximum possible force and survivability, which leads the enemy to make increased estimates of the probability of a disabling counterstrike, and in terms of strategy and politics, the aim is to cause the enemy to believe that such a second strike would be forthcoming in the event of a nuclear attack.
Second strike One of the main reasons to deter a first strike is the possibility of the victim of the first-strike launching a retaliatory second strike on the attacker.
Increasing SSBN deployment Nuclear-powered ballistic missile submarines (SSBNs) carrying
submarine-launched ballistic missiles (SLBMs), commonly known as "boomers" in the US and "bombers" in the UK, are widely considered the most survivable component of the
nuclear triad. The depths of the ocean are extremely large, and nuclear submarines are mobile, quiet, have virtually unlimited range, and can generate their own oxygen and potable water. In essence, their undersea endurance is limited only by food supply. It is unlikely that any conceivable opponent of any nuclear power deploying ballistic missile submarines can locate and neutralize every ballistic missile submarine before it launches a retaliatory strike in the event of war. Therefore, to increase the percentage of nuclear forces surviving a first strike, a nation can simply increase SSBN deployment and the deployment of reliable communications links with SSBNs.
Hardening or mobilizing land-based nuclear assets In addition, land-based ICBM silos can be hardened. No
missile launch facility can really defend against a direct nuclear hit, but a sufficiently hardened silo could defend against a near miss, especially if the detonation is not from a multimegaton
thermonuclear weapon. In addition, ICBMs can be placed on road or rail-mobile launchers (
RT-23 Molodets,
RT-2PM2 Topol-M,
DF-31,
Agni 5,
Agni 6,
MGM-134 Midgetman), which can then be moved around. As an enemy has nothing fixed at which to aim, that increases its survivability.
Increasing alert state and readiness The effectiveness of a first strike is contingent upon the aggressor's ability to deplete its enemy's retaliatory capacity immediately to a level that would make a second strike impossible, mitigable, or strategically undesirable. Intelligence and early warning systems increase the probability that the enemy has the time to launch its own strike before its warmaking capacity has been significantly reduced, which renders a first strike pointless. Alert states such as
DEFCON conditions, apart from serving a purpose in the internal management of a country's military, can have the effect of advising a potential aggressor that an escalation towards first strike has been detected and therefore that effective retaliatory strikes could be made in the event of an attack.
Maintaining survivable C4ISTAR links Looking Glass,
Nightwatch, and
TACAMO are US airborne nuclear command posts and represent survivable communication links with US nuclear forces. In the event of significant political-military tensions between the nuclear powers, they would take to the skies and provide survivable communications in the event of enemy attack. They are capable of the full exercise of all available
MAOs (Major Attack Options), as well as the full
SIOP, in the event of a first strike or the destruction of the
NCA. They can directly initiate launch of all American ICBMs via radio and satellite communication, signal SLBMs to launch and send bombers on their strike missions. In addition to those airborne assets, the
US government has several command and control
bunkers, the most famous of which is that of
NORAD, which is tunneled a few thousand feet into the
granite of
Cheyenne Mountain Complex, outside
Colorado Springs,
Colorado. It is believed to be able to withstand and to continue to operate after a nuclear direct hit. Other US C4ISTAR bunkers include an installation called
Site R, located at
Raven Rock,
Pennsylvania, which is believed to be
the Pentagon's relocation site if
Washington, DC, is destroyed, as well as
Mount Weather, located in
Virginia, which is believed to be the relocation site for top
executive branch officials.
The Greenbrier, located in
West Virginia, was once the site of the
Supreme Court of the United States and
Congress's relocation bunker, but it is no longer a secret but is now a tourist attraction. The Russians have a system called
SPRN (СПРН), which can detect nuclear launches and providing early warning so that any such strike would not be undetected until it is too late. However, their unique and special capability can be found with their
Dead Hand fail-deadly computerized nuclear release system, which is based at
Kosvinsky Kamen in the
Urals. Apparently, Dead Hand, named for either the
dead man's hand in poker or the
dead man's switch in dangerous or deadly machinery, can be turned on whenever the Russian leadership fears a nuclear attack. Allegedly, once Dead Hand is activated, if it detects a loss of communications with Moscow as well as nuclear detonations inside Russian territory, it can give final authority for the release of nuclear weapons to military officers in a bunker under Kosvinsky Kamen, who can then, if they so determine, launch Russia's arsenal.
Decreasing tensions by mutual adoption of minimum credible deterrent posture Instead of relying on sophisticated communications links and launch-on-warning postures, the French, the British, and the Chinese have chosen to assume different nuclear postures more suited to minimum credible deterrence or the capability to inflict unacceptable losses to prevent the use of nuclear weapons against them, rather than pursuing types of nuclear weapons suitable to first-strike use.
China is believed to pursue a
minimum credible deterrent/
second strike strategy with regards to the US. That may or may not be true with regards to China's stance with regard to Russia, as few Chinese nuclear platforms are intercontinental, and most of the platforms are deployed on the Russian-Chinese border. Unlike relations of the US and China, Russia and China have had military conflicts in the past. In recent years, China has improved its early warning systems and has renovated certain of its platforms for intercontinental strike, which may or may not be due to the US missile defense system. In general, it appears that China's leaders do not greatly fear a first strike, because of their posture of inflicting unacceptable losses upon an adversary, as opposed to the American and Russian policy of trying to "win" a nuclear war. The Chinese arsenal is considered to suffice in ensuring that such a first strike would not go unavenged. The United Kingdom and France have sophisticated nuclear weapons platforms, and their nuclear strategies are minimum credible deterrent-based. Both have
ballistic missile submarines, armed with intercontinental
submarine-launched ballistic missiles, to ensure a
second-strike retaliation anywhere in the world. France also has a number of nuclear capable fighter aircraft. Both have nuclear policies that are believed to be effective deterrence towards a would-be nuclear strike against themselves, NATO,
European Union members, and other allies. == Destabilizing role of land-based MIRVed ICBMs ==