Two deep fallacies undermine this argument. First is the premise itself — that a different Russian leader might seek an accord to withdraw troops from Ukraine. No one who hopes to secure power in Moscow, however, could ever accept Ukraine’s entry into NATO or the presence of hostile troops on Ukrainian soil. Any Russian president who did so would be seen as exposing his country to mortal danger and quickly deposed. Removing Putin would not alter Russia’s determination never to tolerate an enemy army on another of its borders.

The second and more illuminating argument against killing foreign leaders is the poor record we have in past attempts. We’ve tried it repeatedly. Often we have failed, but even when we seem to have succeeded, the long-term consequences have been terrible. An order from the Oval Office to assassinate a foreign leader would not break a taboo. It would only be the latest in a series of self-defeating blunders.

So far as is known, Dwight Eisenhower was the first president to order such assassinations. He began by targeting Premier Zhou Enlai of China. During the 1950s, Eisenhower and nearly every other policymaker in Washington considered the “Red Chinese” to be maniacal fanatics bent on world conquest. When Zhou announced in 1955 that he would travel to Bandung, Indonesia, for a momentous conference of Asian and African leaders, the CIA saw a chance to kill him. Zhou chartered an Air India jet for his flight to Bandung. It exploded in midair, killing 16 passengers. But Zhou had not boarded. China called it “murder by the special service organizations of the United States.”