Rich Lowry of National Review Online explains the important role Republican National Convention delegates will play in selecting the party’s presidential candidate.

If there is an open convention, Trump will argue that the voters should rule, not delegates no one has heard of, selected at obscure precinct, county, district, and state meetings. He will, in short, declare the entire exercise of a contested convention illegitimate.

Is it? We are used to the voters’ directly deciding, and should Trump perform strongly enough to win a majority of delegates, 1,237, they, in effect, will. But if he falls short, the delegates enter the picture.

The requirement for a majority of delegates (Trump once decried this rule as arbitrary) is meant to ensure that the nominee is, as much as possible, the consensus choice of the party. Ordinarily, this isn’t an issue — the early leader in a nomination fight vanquishes the opposition and steadily consolidates the support of the party.

In 2012, Mitt Romney didn’t lose a contest after March 24. His closest competitor, Rick Santorum, dropped out shortly after losing Wisconsin on April 3, and after that, Romney was racking up victories with 60 percent of the vote or more.

For Trump — who spent last week threatening and mocking Ted Cruz’s wife — this unifying march down the homestretch is hard to imagine. If Trump has only won a plurality of delegates, it won’t be a sign of strength, but of weakness. A badly divided party would be nominating a candidate who couldn’t reach a majority and, so far, has shown no general-election appeal. In this circumstance, delegates would be justified in looking to someone else better suited to win an election and protect the party’s interests. …

… Trump has thrived so far without an extensive, traditional political operation. But politics isn’t only about TV interviews and big rallies. There is a reason that the system also rewards candidates who can motivate and muster people to do the grass-roots activism involved in winning small victories at local meetings. This is literally getting people involved in the process, and it could take on an outsized significance in deciding the immediate future of the Republican Party.