ecent history furnishes Democrats with a painful example of how a party can sabotage its electoral chances when it tries to anoint a preferred candidate. In 2016, all the leading constituencies in the party worked to clear the way for a presumptive nominee: Hillary Clinton.

At the time, this seemed a perfectly reasonable course of action. Clinton would have been the first female president, and she had done an excellent job as a senator from New York and as U.S. secretary of state. Because her nomination seemed all but inevitable, the party elite was chiefly concerned with avoiding an intraparty fight that might weaken her position in the general election.

But attempts to ensure Clinton a virtually unopposed run backfired. As the primaries went on, they exposed the fact that she was much less popular among voters than the conventional wisdom had allowed. Her inability to win a decisive victory against an independent socialist senator who at one time did not even caucus with the Democratic Party served only to highlight her weaknesses.

Significant parts of the Democratic base came to believe that the Democratic National Committee had rigged the primary process, making them less willing to turn out for the general election. In the end, the contest produced the very outcome that the party’s power brokers had tried to avert: It exposed the nominee’s vulnerabilities, created a bitter rift, and helped Trump win the election.