“Umbrella” vs. “Sharing”

NATO was founded in 1949 with the claim that a US ‘nuclear umbrella’ would protect non-nuclear member states. In 2018, the British government affirmed that its nuclear Trident SSBN missiles are part of “the defense of our NATO allies”1. The French government, meanwhile, never made such explicit claims about using its nuclear ‘Force de Frappe’ for non-French interests.

Besides this ‘umbrella’ situation, five out of the 27 non-nuclear NATO member states (Turkey, Italy, Germany, Netherlands, Belgium) have taken part in US nuclear sharing2, since the 1960s: US nuclear free-fall bombs are stored in these countries. In the event of war, fighter-bomber planes and aircrews from these countries are supposed to drop US nuclear bombs on selected targets. As the NATO commander-in-chief is always a US general, European aircrews in the nuclear sharing system function as de facto foreign legionnaires of the USA.

The operational radii of the fighter-bomber aircraft are about 1,000 km, thus (except Turkey) the ‘sharing’ targets are necessarily in European region. Given NATO’s overall posture in Europe, Russia is presumably the main target.

In this precision guided missile era the dropping free-fall nuclear bombs from decades-old manned aircraft is dangerous for the air crew. In order to drop the bomb the aircraft has to take a flight path over its target. What chance does a German nuclear fighter-bomber Tornado – a 50 year old ‘veteran’ – have to penetrate modern air defence systems?

Differing risks for NATO members

Nuclear sharing illustrates different levels of risk among the NATO states: 22 non-nuclear NATO member states are allegedly “protected” passively by the US “nuclear umbrella”. For the 5 “sharing” states this “umbrella” has holes, as they – and only they – are commanded to become accomplice to actions which otherwise would legally burden the USA alone, who are the owner state of the nuclear weapons. The US nuclear airbases in the “sharing” states obviously present high-ranking targets for any US adversary. In none of the five NATO states was nuclear sharing ever put to a public vote3. France, Czech Republic, Denmark and Iceland do not allow US bases in their territory. Iceland doesn’t even have a military. Thus even neighbouring NATO states carry widely differing risks.

“Sharing” dependent on personal decision

The functionality of nuclear sharing has a peculiarity: It doesn’t depend on government or military decisions. Instead it is up to the will of individuals, in this case air force personnel being citizens of the ‘sharing’ states. In the decision of such air force personnel to obey or refuse a nuclear command the following should be considered:

(a) the consequences of personal insubordination,

(b) the consequences of being accused as a war criminal at the International Criminal Court (ICC) in The Hague (Netherlands) and

(c) personal, moral and related aspects.


If air force personnel refuse the command to deploy nuclear bombs, they might have a setback in their professional career, but nothing more. European ‘sharing’ states no longer shoot ‘disobedient soldiers’, as historic predecessors regularly did. This liberalization removed an ancient principle of the military: The soldier follows blindly the commands from the political leadership, they are not to ask questions. The ‘sharing’ air force personnel are citizens of democracies. They will have experienced the fact that democratic governments can fail and even lie to the public regarding the ‘justifications’ for war. The most prominent example was the 2003 US/UK Iraq invasion, as has been shown by the 2016 Chilcot Report to the British government.

Each member of a ‘sharing’ fighter-bomber crew has the personal obligation to respect the international law of warfare. To refuse a command which, according to the available information, appears illegal is no insubordination contrary to discipline but a citizen’s obligation. If the air force personnel happens to be a German citizen, they are expressly obliged to obey international law by the constitutional ‘Basic Law’.

Air force personnel as professional soldiers are trained and familiar with the international law of warfare, including awareness of its rapid development concerning nuclear weapons in the recent decades. This culminated in the Treaty on the Prohibition of Nuclear Weapons (TPNW), which has been in force since January 2021 for the – till present – 54 states which ratified it. It is backed by the consent of 122 of the 193 UN member states. Major European states which have ratified the TPNW are Austria and Ireland. The Treaty has finally internationally stigmatised nuclear weapons in line with chemical and biological weapons. Thus the question “Is a threat or use of a nuclear weapon legal?” is no longer pending, as nuclear weapon states and their entourage kept claiming over decades, but it is answered for good by a general and unconditional “No”.

So theoretically, each crew member has to make a personal decision as to whether a given command to drop a nuclear bomb on a specific target is legal. For the details of this see the work of Robert Forsyth, former Commanding Officer of a British Polaris nuclear ballistic missile submarine, who points out1: the legal situation demands for the soldier (a) to know the identity of the target (which the Polaris crew didn’t) and (b) to assess the damage to be expected at this target from the bomb drop under the given conditions, particularly with regard to civilian collateral damage. For targets in inhabited areas the result is clear: such attacks are illegal.

Concerning nuclear weapons, a German Bundeswehr airman or airwoman is in a legally clear situation: According to the MoD service instructions of 2006, it is forbidden for her or him to use anti-personnel mines, nuclear weapons, bacteriological weapons and chemical weapons5. So he or she doesn’t have the choice but the obligation to refuse a command to drop a nuclear weapon, regardless what the government does.

Accusation of war crime

The Rome statute of 1998, the basis of the International Criminal Court, contains a clear definition of which actions are treated by the court as war crimes. It refers explicitly or implicitly to long existing international law like:

– the Hague Convention of 1907 (prohibiting firing into dwelling quarters),

– the Nuremberg Charter of 1945 (declaring that a command doesn’t free the soldier from his or her obligation to check if this command may be illegal, if he or she had the personal choice to refuse an illegal command),

– the Geneva Red Cross Conventions of 1949 with their Protocol Additional I of 1977 (prohibiting attacks which cannot discriminate between combatants and civilians) and

– the Advisory Opinion of the International Court of Justice (ICJ) of 1996 (declaring both the threat and the use of any nuclear weapon to be illegal).

The US law professor Richard Falk4 adds that the unwritten nuclear taboo (never to use nuclear weapons) has been in effect for more than seven decades and therefore is evidence that it is a customary legal norm.

Since 2002 the ICC searches, prosecutes, judges and punishes war criminals. Following the Rome statute and seeing the effects of nuclear weapons, the use of a nuclear weapon in an inhabited area is unavoidably a war crime, regardless of weapon yield and air or ground burst. In other words: No scenario is known where use of a nuclear explosion in an inhabited area could be legal.

The ‘sharing’ air force personnel who pressed the nuclear button and survived the mission flight despite air defence finally will stand alone in front of the ICC. Except for the US and Turkey, all NATO states are members of the Rome statute. Thus the US denies the responsibility of the ICC for actions of their military personnel which might be assessed as war crimes according to the Rome statute definition. This may be formally right, but is it acceptable for NATO’s supreme command? In the case of nuclear sharing the US will – perhaps rightfully – argue that the ‘sharing’ air force personnel were not their citizens so the US are not involved. NATO will – perhaps rightfully too – refuse any responsibility for nuclear sharing and will point to the national government of the personnel concerned. However, this government will not be able to protect its personnel from the ICC procedures. In case of a ‘sharing’ nuclear explosion the responsible government officials (MPs, MoD and air force command chain) will to be accused at the ICC too, comparable to the Nazi offenders at the Nuremberg tribunal from 1945.

Before the TPNW came into force the ‘sharing’ air force personnel could claim for her or his defence that they trusted, in good faith, the legality of the actions and commands of their government to which they may have sworn an oath of loyality. With the TPNW in force it is no longer a debatable political opinion but an undisputable fact, regardless of whether a particular government has signed the treaty or not: The military strategies of the nuclear weapon states and their entourage are based on the preparedness to commit monstrous war crimes.

Personal aspects

If the air force personnel has family she or he might think about their children at home who will ask one day what they had done in the war. Shall they tell them: “I pressed the button and killed some ten or even hundred thousand people. For a similar number of surviving people I made their future life hell. These people had never harmed our country. I made their country uninhabitable for generations. This crime carries my name. I could have refused the command but I obeyed”?

The airman or airwomen knows that ‘the system’ or ‘the politicians’ do not press the nuclear button, but they themselves according to their free will. They also might think about how for the rest of their life they will be chased in their dreams by the nightmare scenes on the target ground, either learnt from media reports or from their own imagination. They wouldn’t only ruin the lives of the victims. They would ruin their own and their family’s lives too.

And even if they somehow escaped punishment by the ICC: their name as a crew member responsible for the nuclear bombing will be in the history files. Therefore they might expect personal revenge by a secret service of the victim state or even privately by survivors who will trace and find them. Similar has happened: In 2002 a midair collision of two airliners occurred over Southern Germany, killing 71 people including 49 children. In 2010 the father of a victims family met the responsible ground based air traffic controller who had ‘mis-performed’ and stabbed him to death.

Nuclear sharing in retreat

NATO claims that the TPNW is irrelevant because the nuclear weapon states and their entourage are not members. This is formally correct. But since the TPNW, according to the will of the majority of the UN states, stigmatises nuclear weapons like chemical and biological weapons, there is no longer space for claims that there are conditions under which the use of nuclear weapons might be legal.

A side problem for NATO is that non-NATO countries consider the US nuclear sharing a violation of the nuclear Non-Proliferation Treaty (NPT) of 1970 and an illegal nuclear proliferation: After take-off the non-US national air crew has the power of disposal over a nuclear weapon. Exactly this is prohibited by the NPT. For instance the crew could decide to desert and emergency-land with the nuclear weapon on enemy ground.

To further illustrate the problem, one may think about a fictional nuclear sharing, legally a copy of NATO’s action: Saudi-Arabian or Iranian aircraft carry nuclear bombs shared by Pakistan as the owner state.

NATO member state governments keep claiming that the 1996 advisory opinion of the ICJ is ambiguous for the extreme case that nuclear weapon use is the “Last Resort” to save the very existence of a state, and therefore it could be legal (on this question the ICJ judges voted 7:7 undecided). Whatever this could mean for a nuclear weapon state, such a “Last Resort” scenario can only be valid for the nuclear weapon state itself, not for any third parties like its allies, thus not for the five European states involved in nuclear sharing.

Will there be at any time any Turkish, Italian, German, Belgian or Dutch air force personnel of clear mind and morality prepared to obey a command to drop a nuclear bomb on any target in Europe? How will the air forces of the five European nuclear sharing states under the TPNW – regardless if signed by them – recruit their nuclear bomber crews? What will be the result of an open public discussion on this question? It looks like the TPNW indeed has deflated US nuclear sharing.

Steadfast Noon

An open question will probably remain as to whether the participation of air force personnel of the “sharing” states in the yearly NATO maneuver ‘Steadfast Noon’ is legal. With or without nuclear bomb mockups, nuclear missions are practiced in this maneuver. Is it a threat against Russia and her ‘allies’? According to the ICJ 1996 Advisory Opinion it is. The ‘sharing’ governments may claim it isn’t. By principle a valid statement could be obtained from the ICC following an accusation from a state which might see itself as threatened, as a member of the Russian-led “Collective Security Treaty Organization” (CSTO): Russia, Armenia, Kazakhstan, Kyrgyzstan, Tajikistan, and Uzbekistan. But these states are not members of the Rome statute, with the exception of Tajikistan. This country, however, is located more than 2,000 km from the nearest NATO area (eastern Turkey), so technically it is out of range of US ‘nuclear sharing’.


1 Robert Forsyth, Why Trident?, Nottingham 2020: Spokesman, ISBN 978-0-8512-4890-5.

2 Nuclear Sharing: the facts, END Info Issue 22, February 2021, Russell Peace Foundation.

3 Beatrice Fihn and Daniel Hogsta, Changing Europe’s Calculations – Treaty on the Prohibition of Nuclear Weapons, The Spokesman No. 147, February 2021, Russell Peace Foundation, ISBN 978-0-8512-4895-0.

4 Richard Falk, Challenging Nuclearism, The Spokesman No. 147, see above.

5 Bundesministerium der Verteidigung R II 3, Druckschrift Einsatz Nr. 03 Humanitäres

Völkerrecht in bewaffneten Konflikten – Grundsätze, August 2006, DSK SF009320187,