Among the nuclear-weapon-complicit states, Belgium, Germany, Italy, the Netherlands, and Turkey have a particular, operational role in assisting and encouraging the retention of nuclear weapons. They host approximately 150 American B-61 nuclear gravity bombs between them on their metropolitan territories, as shown on the map above.
The B-61 bombs are assumed to have explosive yields ranging from an equivalent of 0.3 to 170 kilotons of TNT. They are believed to be located at six bases: Kleine Brogel Air Base in Belgium; Büchel Air Base in Germany; Aviano and Ghedi air bases in Italy; Volkel Air Base in the Netherlands; and Incirlik Air Base in Turkey. The “deterrent” value of these foreign-deployed nuclear weapons is a subject of debate.
The respective hosting arrangements are thought to be governed by classified bilateral agreements between the United States and the host states. Representatives of the host states have traditionally been reluctant to discuss their governments’ hosting policies, in part due to the classification of the respective hosting arrangements as state secrets. In 2013, two former Dutch prime ministers publicly confirmed that the Netherlands hosts nuclear weapons. Ruud Lubbers, prime minister from 1982 to 1994, stated that he “would never have thought those silly things [nuclear bombs] would still be there in 2013”. Dries van Agt, prime minister from 1977 to 1982, said the bombs “are there and it’s crazy they still are”. Both were threatened with prosecution, but formal charges were never laid.
The nuclear weapons stored in Belgium, Germany, Italy, the Netherlands, and Turkey are all believed to be under the control of the United States. Yet arrangements are reportedly in place for the bombs to be transferred to and used by the host state in an emergency. Belgium, Germany, Italy, and the Netherlands all have a nuclear role and retain nuclear-capable aircraft and pilots trained in the use of the weapons at the bases in question. The aircraft are sometimes referred to as “dual-key”, as their employment of nuclear weapons would have to be approved both by the US government and the government of the respective host state. In the case of the B-61 bombs stationed at Incirlik in Turkey, however, any use of the weapons would reportedly be carried out by aircraft stationed at other bases, but it is not known whether they are US or Turkish aircraft. There are ostensibly no nuclear-capable aircraft at Incirlik.
There have been several attempts by European policymakers to have the remaining weapons removed from European soil. For example, in 2005, the Belgian Senate unanimously adopted a resolution calling for the removal of nuclear weapons from Belgian territory. In 2009, the German coalition government committed through its governing platform to have the remaining nuclear weapons in Germany withdrawn. The then Foreign Minister Guido Westerwelle promoted the initiative enthusiastically for some time, but the United States responded negatively, and the initiative was quietly shelved the next year. At the NATO summit in 2018, the allies collectively declared that NATO’s deterrence posture “relies on the United States’ nuclear weapons forward- deployed in Europe and the capabilities and infrastructure provided by Allies concerned."
 T. Sauer and B. van der Zwaan, “U.S. Tactical Nuclear Weapons in Europe After NATO’s Lisbon Summit”, Harvard Kennedy School (2011).
 For a review of this issue see: Todd Sescher, “Sharing the Bomb” (2017).
 H. M. Kristensen, “Nukes in Europe: Secrecy Under Siege”, Federation of American Scientists (13 June 2013).
 Nuclear Threat Initiative, “One-time Leaders May Face Charges for Discussing Dutch-Based Nukes” (14 June 2013).
 H. M. Kristensen and R. S. Norris, “Worldwide deployments of nuclear weapons, 2017”, Bulletin of the Atomic Scientists 73, no. 5 (2017).
 Nuclear Threat Initiative, “Belgian Senate Calls for Removal of U.S. Nukes” (22 April 2005).
 M. Skjønsberg, “Nato og amerikanske kjernevåpen i Europa”, Internasjonal Politikk 75, no. 2 (2017), pp. 187–88.
 NATO, “Brussels Summit Declaration” (11 July 2018).