The Munich Security Conference (MCI) has for decades been a place where dialogue about controversial security issues is central. Complicated issues like the Iranian nuclear programme and talks between estranged neighbours, like Israel and Palestine or the USA and Russia, were on the agenda and could be discussed in public and behind closed doors. This year’s 57th conference on 19 February was totally dissimilar to the previous 56 meetings.

The Treaty on the Prohibition of Nuclear Weapons (TPNW) entered into legal force on 22 January 2021. It is the first multilateral nuclear disarmament treaty to be negotiated in 25 years (since the Comprehensive Nuclear-Test-Ban Treaty, CTBT) and the first such treaty to enter into force in 49 years (since the Seabed Treaty which prohibits weapons of mass destruction including nuclear weapons being placed on the seabed).

The entry into force of the Treaty on the Prohibition of Nuclear Weapons (TPNW) on 22 January 2021 yields strong and mixed emotions. Advocates expect an acceleration of the climb to the summit of Mountain Global Zero. Opponents repeat that the nuclear-armed states will never sign the Treaty. If the nuclear-armed states are not willing to ban nuclear weapons, though, the odds are that others will not believe their promises to eliminate nuclear weapons, as required by the Nuclear Non-proliferation Treaty (NPT). That does not bode well for the NPT, the “cornerstone” of the nuclear non-proliferation and disarmament regime.

In 1984, President Ronald Reagan noted the nuclear emperor had no clothes: “The only value in our two nations [U.S. and Soviet Union] possessing nuclear weapons is to make sure they will never be used. But then would it not be better to do away with them entirely”? Indeed it would. The Treaty on the Prohibition of Nuclear Weapons (TPNW) tries to do so through a new normative settling point on the ethics, legality and legitimacy of the bomb.

Critics of nuclear weapons have long pointed to two sets of risks. First, deterrence stability depends on all fail-safe mechanisms working every single time in every bomb-possessing country. That is an impossibly high bar for nuclear peace to hold indefinitely. Second, it also requires that rational decision-makers be in office in all the world’s nine nuclear-armed states.

Since the dawn of the nuclear age in 1945, perceptions and strategic positions amongst States regarding nuclear weapons have always differed. The 2017 Treaty on the Prohibition of Nuclear Weapons (TPNW) has thrust these existing divisions to centre stage. The treaty is the result of an increasing emphasis placed by non-nuclear weapon States on the humanitarian consequences of nuclear weapons and the persisting risks posed to all humanity by these weapons.