In the United States, the specter of Chamberlain is invoked any time Barack Obama does something that Bill Kristol doesn’t like. But this time, the comparison is apt. It is not so much that Cameron is guilty of appeasement, though there is certainly an element of that: He proposed this foolish referendum in 2013 to appease the nationalists in his Conservative Party and outflank the U.K. Independence Party. Rather, he is like Chamberlain in the respect that world leaders are defined by one, maybe two major decisions in the cold glare of history—and this is especially true in the case of disastrous decisions. Whether Great Britain actually leaves the European Union remains an open question, and members of the “Leave” campaign, including former London Mayor Boris Johnson, seem startled that the vote has suddenly turned into something more than an opportunity to grandstand. But Cameron will always be remembered as the guy who brought Britain to this point, literally risking his entire country’s future for short-term political gain.