But the rules in the Republican primaries, as we are now seeing, are not ideally designed to create consensus. Trump hasn’t won a majority in any contest so far — and he could in theory keep failing to win majorities and still come to the convention with a delegate lead. If he had a majority of the delegates, even his fiercest opponents within the Republican Party would have to concede that he had won fair and square. Republican opposition to his nomination would fade, too, if he had a big plurality built by a lot of state majorities.
Different rules, as Francis Barry has written, could make it more likely that in the future party nominations will go to candidates with majority support. States could, for example, hold runoff elections between the top two candidates in a primary. Or they could hold “instant runoffs.” Take a race with three candidates. Voters could rank those candidates. If none of them got 51 percent of voters to say he was their first choice, the candidate with the fewest votes would be eliminated. Then his voters would be reallocated to their second-choice candidate. The winner would then be preferred by the majority.
It’s not too late to apply some version of this idea to the choice of a Republican nominee. Republicans could change the rules of their convention to permit some kind of preferential ballot. The rule change would have to be proposed in advance, so that members of the convention’s rules committee have time to consider it before voting on it during the week before all the delegates arrive in Cleveland. Then, if it passes the committee, a majority of delegates would have to vote for it too.
When it came time for the delegates to vote on the presidential nomination, delegates would rank their candidates — with pledged delegates putting the candidates to whom they are pledged at the top of their lists. It would probably also be necessary—to reduce the likelihood of accusations of dirty tricks — for each delegate to make his or her rank orderings public immediately after the vote.