Because many of our fellow citizens have never experienced a “contested” convention, one which went beyond the first ballot, there is some confusion about how this works. Only an absolute majority of the delegates assembled in the convention can select an individual as the party’s candidate for the presidency.
It is not correct that a candidate who enters the convention with a plurality of delegates, although short of a majority, must receive the nomination. Such an interpretation would be a gross violation of the essential purpose of the nominating process.
If that were the rule, Abraham Lincoln would never have been president. He came in second on the first ballot at the 1860 Republican convention, but won the nomination—with a majority of the delegates—on the third ballot. In 1976 Ronald Reagan got a million more votes than President Ford in the primaries. But Reagan did not win a majority of the delegates, President Ford did, and so he received the nomination.
Reagan understood the rules. Without complaint, he supported the winner. That’s how it works.