Different nuclear conflict scenarios would differ hugely in how harmful they'd be in the near-term and in how much existential risk they create. In light of this, it is useful to have a clearer sense of the likelihood that nuclear conflict would involve two or more attacking countries, rather than just one.

Will the next offensive nuclear detonation(s) be retaliated against, if such a detonation occurs by 2024?

This question resolves positively if, by 2024:

There are one or more offensive nuclear detonations of nuclear weapons owned by some country, and
Within 30 days of the first of those detonations, there is at least one offensive detonation of another country's nuclear weapon, against the country who owned the previously detonated nuclear weapon(s).

For the purposes of this question, offensive nuclear detonations include deliberate, inadvertent, or accidental/unauthorised detonations (see the fine print for definitions). For simplicity, no attempt will be made to account for whether the detonation against the country who owned the previously detonated nuclear weapon(s) is truly a "retaliation" or even whether it's by a country directly harmed by the original detonation(s); it just needs to occur within 30 days.

This question resolves ambiguously if there is no offensive nuclear detonation a nuclear weapon owned by any country before 2024.

Related Questions

Will >100 offensive nuclear detonations occur by 2024, if there's at least 1 fatality from an offensive detonation by 2024?
How many nuclear weapons will be detonated offensively by 2050, if at least one offensive detonation occurs?

The military significance or stated purpose of the strike is not taken into consideration for this question (except that detonations for testing purposes and peaceful nuclear explosions are not counted towards positive resolution). Test detonations and peaceful nuclear explosions are defined as detonations which are claimed as being a test or a peaceful nuclear explosion by an official government communication within 30 days of the event, without this being disputed by reliable media, state reports, or multinational reports. If information is unclear, then resolution will be left up to Metaculus admins.

In a deliberate detonation, the attacking nation decides to launch one or more nuclear weapons either in response to a genuine nuclear attack or without believing that it is under nuclear attack. “In an inadvertent detonation, the attacking nation mistakenly concludes that it is under nuclear attack and launches one or more nuclear weapons in what it believes is a counterattack” (Barrett et al., 2013). “In an accidental or unauthorized launch or detonation, system safeguards or procedures to maintain control over nuclear weapons fail in such a way that a nuclear weapon or missile launches or explodes without direction from leaders” (Barrett et al., 2013).