Of course, there were occasional lunatic exceptions to the rule. Since 2006, when the unhinged North Korean regime acquired nuclear weapons, the world has periodically dismissed the zany threats from the Kim dynasty. Kim Jong Un has sporadically warned he might strike Japan, South Korea, and the United States—usually in an outrageous and outlandish fashion.

Kim finally was warned of the consequences of his brinkmanship rhetoric, most famously by Donald Trump in 2018. He reminded Kim that the American nuclear button was bigger than North Korea's—an eerie counter-warning that for a time led to the cooling of North Korean rhetoric.

Pakistan went nuclear in 1998. From time to time, its prime ministers have warned India that in any confrontation, what Pakistan lacked in numbers and arms would be made up by the preemptive use of nuclear weapons. But again, Pakistan's threats, like those of Kim Jong Un's, were dismissed as the rantings of the insecure and blustering, who were otherwise deterred by much larger nuclear arsenals.

But the February 2022 Russian invasion of Ukraine opened a new chapter in nuclear trash-talking. The Ukrainian war has proved dangerously unique in a variety of ways. True, there have been prior large land wars involving nuclear powers. The first Gulf War of 1991 saw Britain, France, and the United States combine to help crush Iraq without mention of nuclear arms. The Soviet Union invaded Afghanistan in 1979 without such threats. Neither did China mention a nuclear option in 1979, despite a less-than-successful short invasion of Vietnam. Nor did Great Britain, in its 1982 retaking of the Falkland Islands, talk of the bomb, although recently declassified documents revealed that the Royal Navy carried 31 nuclear weapons on its expeditionary fleet—presumably depth charges, bombs, and missiles—to the chagrin of the current Argentine government.