United States Nuclear Forces

American strategic delivery systems are divided into a triad, or three different modes of delivering nuclear weapons to the other side's targets. The nuclear triad consists of long-range bombers, land-based intercontinental ballistic missiles (ICBMs), and submarine-launched ballistic missiles (SLBMs). This division of delivery systems provides the foundation of deterrence by assuring that each side has a second-strike capability if attacked.

In 2005, the retirement of the MX Peacekeeper ICBM was completed. Also, the Navy decommissioned the Trident I C4 missile, after 26 years of service. The navy completed the first phase of downloading the warheads from all Trident II missiles in 2005 to keep pace with 2002 Moscow Treaty or StrategicOffensive Reductions Treaty (SORT) goals.

ICBMs

Name	Launchers	Warhead x yield (kilotons)	Total warheads
Minuteman III:	400		600
Mk-12	(200)	1-3 W78 x 335 (MIRV)	(600)
Mk21/SERV	(200)	1 W87 x 300	(200)
Total	400		800

Submarines

Name	Launchers	Warhead x yield (kilotons)	Total warheads
Ohio-Class	14	Trident II D-5
		Mk-4A: 1-8 W76-1 x 90 (MIRV)	1,489
		Mk-4A: 1-2 W76-2 x low (MIRV)	50
		Mk-5: 1-8 W88 x 455 (MIRV)	384
Total	14		1,920

Bombers

Name	Launchers	Warhead x yield (kilotons)	Total warheads
B-2A Spirit	20/16	ALCM/W80-1 x 5-150	528
		B61-7 x 10-360/-11 x 400	322
B-52H Stratofortress	87/44	B83-1 x low-1,200	-
Total	72 (active)		850

US TACTICAL NUCLEAR DELIVERY VEHICLES

Virtually every military fighter, or attack airplane can deliver nuclear bombs. Such short-range air-delivered nuclear weapons, operated by the US Air Force, have not been curtailed by any treaty or unilateral initiative. Land-based and sea-based tactical nukes, as they are called, have been removed by treaty mandate or unilateral initiatives. Some have been destroyed and others stockpiled. Deployed tactical nuclear weapons are now restricted to various modifications to the B-61 gravity, or free-fall, bomb. US aircraft capable of delivering this weapon are the A-4, A-6, A-7, AV-8B, F-4, F-15, F-16, F-18, F-111, and presumably the F-117 stealth fighter. NATO aircraft so capable are the F-4, F-100, F-104, and the Tornado.

Source: Bulletin of Atomic Scientists and Federation of American Scientists