The US nuclear forced posture has changed considerably since the end of the Cold War in 1990. The force declined in size, some nuclear delivery vehicles and a variety of nuclear bombs and warheads have been taken out of service, mostly to meet commitments made under various arms control treaties signed with the Soviet Union/Russia, leaving a much more consolidated force in service. However, that force is very active, especially the submarine component of it, and is ready to execute war orders from the President on a moment's notice.
All operational responsibility for nuclear weapons and delivery systems rests with US Strategic Command. Within Stratcom, nuclear responsibilities, including responsibility for nuclear war plans, belongs to Joint Force Component Commander for Global Strike. There are two service components within JFCC-GS: Air Force Global Strike Command is responsible for the Air Force legs of the triad, the ICBMs and the bombers. Navy Fleet Forces Command controls the ballistic missile submarine force. Within the Navy, the Strategic Systems Programs office is responsible for the Navy's nuclear weapons enterprise, including development and maintenance of the missiles, and onboard targetting systems, warhead security and cooperation with the British Royal Navy on their part of the Trident program.
The most survivable, and most important leg of the nuclear triad is the Navy's fleet of 14 Ohio-class nuclear-powered ballistic missile submarines. They are divided between the East and West Coasts, with 8 assigned to Bangor, Wash. and 6 assigned to Kings Bay, Ga. (Minus the three currently reported as in drydock maintenance, including 2 from Bangor and one from Kings Bay). Each sub has 24 launch tubes for the Trident D5 missile (this is to be reduced to 20 under the New START treaty), and each missile is capable of carrying 4-8 warheads of either the W76 or W88 types, though the maximum number that theyre actually carrying has reportedly been reduced to 6 to meet treaty limitations. The W76 has a yield of 100 KT, and the W88 of 475 KT. The Congressional Research Service reported, last February, that the Navy maintains 240 Trident missiles to support deployments and another 50 for the Royal Navy. The total stock is larger than that, of course, to support the deployed fleet, since a number of unarmed missiles are fired in the Atlantic and Pacific test ranges every year. The Navy has been buying 24 missiles per year for the last few years to meet these requirements.
According to data provided by the Navy in response to an EIR Freedom of Information Act request, the Navy's ballistic missiles submarine fleet executed 38 deterrent patrols in 2009, 33 in 2010 and 28 in 2011. That decline is entirely accounted for by the Pacific-based boats, which executed 28, 20, and 17 deterrent patrols each over those three years while the number of patrols by the Atlantic fleet boats remained relatively stable. While the Navy discloses little information about deterrent patrols, we can surmise from the patrol numbers that the Navy is able to maintain 4-6 boats on patrol at any one time, and has the capable to surge up to 9-10 boats on short notice.
The second leg of the triad is the land-based ICBM force, which consists of 450 Miniuteman III missiles spread out in North Dakota, Montana, and Wyoming. These missiles have been in service since the 1970s but have undergone service life extension programs since that time. The Minuteman III was born to carry 3 warheads each, but under New START, these are to be reduced to one warhead, each. Air Force officials have reported that this process is underway. The above-cited CRS report from last February indicates, however, that the Air Force may retain the ability to re-upload the missiles to the three-warhead configuration "if the international security environment changed." The same CRS report also reported that the Air Force was on track to complete replacement of the W62 and W78 warheads that had originally equipped the Minuteman fleet with the W87 warheads that had originally been deployed on the MX Peacekeeper missiles which were removed from service by 2005 under the START II treaty. The W87 is reported to have a yield of 300 KT.
During the Cold War there was a great deal of fear that the Soviets had the capability of counter-force targetting the US ICBM force, since the location of each missile silo was known down to the inch, leading to a "use it or lose it" mentality. But with the collapse of the Soviet Union, that fear has also collapsed, leaving the ICBM force as a potent second strike force backing up the submarine force.
The third, and smallest, leg of the nuclear triad is the Air Force bomber force, made up of 20 B-2's and 76 B-52's, though only 16 B-2's and 44 B-52's are designated as primary mission aircraft, the rest being reserved for training. The advantage of the bombers is said to be that they can be deployed anywhere in the world where the US has bases, making them visible elements of the US commitment to its allies. The B-2 can carry either the B61 or the B83 bomb. There are four versions of the B61 bomb. The B-2 carries the B61-7 which has a maximum yield of 340 KT. The B83 has a maximum yield of 1.2 MT, making it the largest nuclear weapon on US service. It is apparently intended for use against hardened targets. The CRS report put the total number of B61 and B83 bombs at about 550. The B-52's carry either the Air-Launched Cruise Missile (ALCM) or the Advanced Cruise Missle (ACM), which is said to be stealthier than the ALCM. Both are equipped with the W80 warhead, the yield of which is variable from 5 to 150 KT. While the bombers are regulated by New START, the individual bombs and cruise missiles are not, so it seems that there may be as many as 2,000 total in inventory, though most are kept at storage locations separate from the bomber bases.