The world has been fortunate to only see nukes used aggressively against one nation, nearly eighty years ago, during the waning days of the Second World War (of course this is small comfort to the hundreds of thousands of victims in Hiroshima and Nagasaki).
This is all the more surprising considering we now have nine countries with nuclear weapons, some of which have been governed by certifiable mass murders (e.g., Stalin and Mao) or by men with questionable moral positions on ordering nuclear strikes (e.g., Nixon). One would think sheer probability would have resulted in at least an accidental launch (of which we have had several close calls).
This got me wondering how this select group of nuclear-armed countries approach the weighty issue of using their nukes against another nation. The most recent and reliable source I could find is a 2018 article from the Council on Foreign Relations, which offers a country-by-country breakdown on the “no first use” policy, the position that nukes should never be used first in any conflict but only in retaliation to a nuclear strike.
Based on the article, I made the following map, which shows the distressing rarity of that commitment:
As explained in the article:
A so-called NFU pledge, first publicly made by China in 1964, refers to any authoritative statement by a nuclear weapon state to never be the first to use these weapons in a conflict, reserving them strictly to retaliate in the aftermath of a nuclear attack against its territory or military personnel. These pledges are a component of nuclear declaratory policies. As such, there can be no diplomatic arrangement to verify or enforce a declaratory NFU pledge, and such pledges alone do not affect capabilities. States with such pledges would be technically able to still use nuclear weapons first in a conflict, and their adversaries have generally not trusted NFU assurances. Today, China is the only nuclear weapon state to maintain an unconditional NFU pledge.
Given that such pledges are not binding, it is odd that more nations do not make them anyway; China’s lone commitment to this stance—which only India comes close to echoing—may not count for much, but clearly it carries enough significance for other nuclear powers to avoid it.
In fact, the United States had previously considered adopting an NFU policy, but has refrained from doing so out of fear that it might indicate insufficient deterrence of foreign threats:
During the Cold War and even today, the credible threat of the United States using its nuclear weapons first against an adversary has been an important component of reassuring allies. At the height of the Cold War, the threat of U.S. tactical nuclear use was conceived of as a critical bulwark against a conventional Soviet offensive through the Fulda Gap, a strategically significant lowland corridor in Germany that would allow Warsaw Pact forces to enter Western Europe. A nuclear first-use policy was thought to be a cornerstone of the defensive posture of the North Atlantic Treaty Organization (NATO), given the large number of bases of Warsaw Pact conventional military forces. Accordingly, NATO has always opposed a U.S. NFU declaration and has never ruled out U.S. first use under its “flexible response” posture since 1967. Today, U.S. allies in East Asia and Europe alike rely on credible commitments from the United States to use nuclear weapons first to deter major nonnuclear threats against them.
I guess these pledges are not so vacuous after all.