"Nuclear forces based in Europe and committed to NATO provide an essential political and military link between the European and the North American members of the Alliance. The Alliance will therefore maintain adequate nuclear forces in Europe."
"Although technically owned by the U.S., nuclear bombs stored at NATO bases are designed to be delivered by planes from the host country."
"The Department of Defense, in coordination with the Department of State, should engage its appropriate counterparts among NATO Allies in reassessing and confirming the role of nuclear weapons in Alliance strategy and policy for the future."
Is Italy capable of delivering a thermonuclear strike? Could the Belgians and the Dutch drop hydrogen bombs on enemy targets?...Germany's air force couldn't possibly be training to deliver bombs 13 times more powerful than the one that destroyed Hiroshima, could it?
The above is from the opening paragraph of a feature in Time magazine's online edition of December 2, one entitled "What to Do About Europe's Secret Nukes."
In response to the rhetorical queries posed it adopts the deadly serious tone befitting the subject in stating, "It is Europe's dirty secret that the list of nuclear-capable countries extends beyond those -- Britain and France -- who have built their own weapons. Nuclear bombs are stored on air-force bases in Italy, Belgium, Germany and the Netherlands -- and planes from each of those countries are capable of delivering them."
The author of the article, Eben Harrell, who wrote an equally revealing piece for the same news site in June of 2008, cites the Federation of American Scientists as asserting that there are an estimated 200 American B61 thermonuclear gravity bombs stationed in the four NATO member states listed above. A fifth NATO nation that is home to the warheads, Turkey, is not dealt with in the news story. In the earlier Times article alluded to previously, author Harrell wrote that "The U.S. keeps an estimated 350 thermonuclear bombs in six NATO countries."  They are three variations of the B61, "up to 10 [or 13] times more powerful than the Hiroshima bomb"  - B61-3s, B61-4s and B61-10s - stationed on eight bases in Alliance states.
The writer reminded the magazine's readers that "Under a NATO agreement struck during the Cold War, the bombs, which are technically owned by the U.S., can be transferred to the control of a host nation's air force in times of conflict. Twenty years after the fall of the Berlin Wall, Dutch, Belgian, Italian and German pilots remain ready to engage in nuclear war." 
The B61 is the Pentagon's mainstay hydrogen weapon, a "lightweight bomb [that can] be delivered by...Air Force, Navy and NATO planes at very high altitudes and at speeds above Mach 2."
Also, it "can be dropped at high speeds from altitudes as low as 50 feet. As many as 22 different varieties of aircraft can carry the B61 externally or internally. This weapon can be dropped either by free-fall or as parachute-retarded; it can be detonated either by air burst or ground burst." 
The warplanes capable of transporting and using the bomb include new generation U.S. stealth aircraft such as the B-2 bomber and the F-35 Lightning II (multirole Joint Strike Fighter), capable of penetrating air defenses and delivering both conventional and nuclear payloads.
The Pentagon's Prompt Global Strike program, which "could encompass new generations of aircraft and armaments five times faster than anything in the current American arsenal," including "the X-51 hypersonic cruise missile, which is designed to hit Mach 5 -- roughly 3600 mph,"  could be configured for use in Europe also, as the U.S. possesses cruise missiles with nuclear warheads for deployment on planes and ships. But the warplanes mandated to deliver American nuclear weapons in Europe are those of its NATO allies, including German Tornados, variants of which were used in NATO's 1999 air war against Yugoslavia and are currently deployed in Afghanistan.
There are assumed to be 130 U.S. nuclear warheads at the Ramstein and 20 at the Buechel airbases in Germany and 20 at the Kleine Brogel Air Base in Belgium. Additionally, there are reports of dozens more in Italy (at Aviano and Ghedi) and even more, the largest amount of American nuclear weapons outside the United States itself, in Turkey at the Incirlik airbase. 
Not only are the warheads stationed in NATO nations but are explicitly there as part of a sixty-year policy of the Alliance, in fact a major cornerstone of the North Atlantic Treaty Organization. An article in this series written before the bloc's sixtieth anniversary summit in France and Germany this past April, NATO's Sixty Year Legacy: Threat Of Nuclear War In Europe , examined the inextricable link between the founding of NATO in 1949 and the deployment of U.S. nuclear weapons and delivery systems in Europe. One of the main purposes of founding the Alliance was exactly to allow for the basing and use of American nuclear arms on the continent.
Seven months after the creation of the bloc, the NATO Defense Doctrine of November 1949 called for insuring "the ability to carry out strategic bombing including the prompt delivery of the atomic bomb. This is primarily a US responsibility assisted as practicable by other nations." 
The current NATO Handbook contains a section titled NATO's Nuclear Forces in the New Security Environment which contains this excerpt:
"During the Cold War, NATO's nuclear forces played a central role in the Alliance's strategy of flexible response....[N]uclear weapons were integrated into the whole of NATO's force structure, and the Alliance maintained a variety of targeting plans which could be executed at short notice. This role entailed high readiness levels and quick-reaction alert postures for significant parts of NATO's nuclear forces."