Since around 2018, Chinese experts have concluded that Washington’s nuclear posture now poses increasing challenges to China’s deterrent. In particular, they have been concerned about shifts in U.S. strategy outlined in the Pentagon’s 2018 Nuclear Posture Review. Many Chinese experts have noted that the review highlighted China as a strategic competitor and that it argued for lowering the threshold for the use of nuclear weapons, including in response to certain kinds of nonnuclear attacks. They also noted the report’s emphasis on low-yield nuclear weapons, which could possibly be used to coerce China. Citing the views of analysts such as Elbridge Colby, who served as deputy assistant secretary of defense for strategy and force development in the Trump administration, Chinese experts saw the new U.S. posture as designed, in part, to compensate for the fact that East Asia’s conventional military balance was shifting in China’s favor.


Is there any international law that prohibits the use of nuclear weapon against another country? Considering that the U.S. lowered the threshold for the use of nuclear weapons, including in response to certain kinds of nonnuclear attacks, it makes me wonder if there's any law that prohibits the use of nuclear weapon against another country, and if the consequences of using nuclear weapons is rather low for countries, especially powerful ones.

  • 1
    " If the United States and its Allies and partners do not field sufficient conventional forces to achieve this objective, U.S. strategy would need to be altered to increase reliance on nuclear weapons to deter or counter opportunistic or collaborative aggression in the other theater....U.S. strategy should no longer treat China’s nuclear forces as a “lesser included” threat. The United States needs a nuclear posture capable of simultaneously deterring both countries..." So 27-35 is totally madness. Commented Nov 11, 2023 at 17:35
  • 2
    It would be challenging to meet the usual standards of proportionality, discrimination, etc. with a nuclear weapon, but perhaps not impossible. When it is legal to put a thousand tons of conventional bombs on a target, a one-kiloton bomb would have to look at effects like fallout and where it lands.
    – o.m.
    Commented Nov 11, 2023 at 18:14
  • 2
    Does this answer your question? According to international law, when is first-use nuclear strike justified?
    – meriton
    Commented Nov 11, 2023 at 23:12
  • 6
    "International law" doesn't really exist. It's a loose set of agreements and guidelines that individual nations believe will help them maintain good relations between each other if followed. Maintaining good relations is rarely the primary objective of deploying nuclear arms.
    – Therac
    Commented Nov 12, 2023 at 6:19
  • 2
    "Considering that the U.S. lowered the threshold for the use of nuclear weapons" - do you have a source for this other than the quote in your post? Because that merely claims that "[the U.S.] argued for lowering the threshold for the use of nuclear weapons", not that they actually lowered it.
    – JBentley
    Commented Nov 12, 2023 at 10:59

3 Answers 3


This was considered by the ICJ in 1996, to quote the Red Cross:

On 8 July 1996, the International Court of Justice issued an Advisory Opinion concerning the legality of nuclear weapons. The Court noted the absence of a conventional prohibition on the use of nuclear weapons, but opined that the use of nuclear weapons must comply with the rules and principles of International Humanitarian Law, including the principle of distinction, proportionality and the prohibition of superfluous injury and unnecessary suffering. [my emphasis]

Thus there is no specific treaty or UN resolution which makes the use of nuclear weapons illegal but the use or threat would normally not be "proportional" except in response to a nuclear attack. But the court shied away from stating that their use would be illegal in an extreme circumstance of self-defence.

In practice, war crimes trials are carried out by the victors. So if a country made first use of nuclear weapons, and was defeated, that would be a very different situation de facto to one in which a country made first use, and won.

  • similarly, rules and laws on how to wage war are usually drafted in peace time. But when a nation feels that it has nothing left to lose, these tend to go out the window pretty fast.
    – Jumboman
    Commented Nov 14, 2023 at 11:31

No, there isn't.

But some countries have voluntarily adopted a policy of "no first strike", which says that in case of a war, they will never be the first party to use nuclear weapons against the other. But if the other party uses nuclear weapons, then they reserve the right to strike back with their nuclear weapons.

A "no first strike" policy implies that at least one party will try and ensure that the war is limited to conventional weapons, as much as possible. It would also mean that if they break this policy they would invite international censure. If they have also signed a binding agreement on this with other nations or international organisations, then they would be breaking international laws if they didn't honour the policy.

  • 1
    If a country carries out a first strike, the existence or not of a no first strike policy is unlikely to have any relevance to the international censure which would inevitably follow regardless (assuming there is any meaningful international community remaining).
    – JBentley
    Commented Nov 12, 2023 at 11:02
  • @JBentley I agree. I was thinking from the perspective of powerful countries who agree to supply a country economic benefits and conventional weapons because of their policy of "no first use".
    – sfxedit
    Commented Nov 12, 2023 at 15:13
  • 1
    Only China and India formally maintain a no first use policy. The US, for example, opposes it so nuclear weapons can serve as a deterrent against the invasion of NATO countries. The UK has stated it would only use them as an initial strike in "the most extreme circumstances", to retain some uncertainty with adversaries about when they'd use them. Pakistan and North Korea both implied they'd use them to defend themselves if invaded or attacked.
    – NotThatGuy
    Commented Nov 13, 2023 at 1:44

The typical scenario of using nuclear weapons as depicted in the literature is the massive strike with powerful weapons over the centres of the densely populated cities, civilians clearly being a primary and intended target. This looks like totally a war crime, regardless of the technology of the weapon used.

Here there is an answer to another question, but explaining how exactly why. Even claim that the city has lots of separate 'military objectives' that could be conveniently flattened with the single large bomb, does not actually make that city a valid military target.

Low yield nuclear weapons are mostly feared on because of the concerns that they usage may escalate to scenario as mentioned above.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .