If Republicans are to block Donald Trump’s presidential candidacy at the convention this summer, they will need the help of two separate platoons of delegates: those formally unbound to any candidate and those who are only halfheartedly pledged to support the New York businessman on the first ballot.

Josh Putnam, a political scientist at the University of Georgia who specializes in election math, says that at least 117 of the 2,472 Republican delegates will arrive at the convention in Cleveland, Ohio in July uncommitted, meaning they can vote for anyone.

Of those, 27 are from territories in the Pacific, 28 from the state of North Dakota and 54 from Pennsylvania.

If Trump falls just short of the 1,237 delegates needed to win the nomination — as seems likely — those unbound delegates could put him over the top.

Which means Trump’s opponents will need them to vote for somebody else on the first ballot to keep the show going.

Unbound

If there is no winner on the first ballot, nearly three-quarters of the delegates — more than 1,800 — become instantly unbound.

Most of the others are gradually released as the convention goes through ballot after ballot trying to find a candidate. Only a few states demand that their delegates stick with the person they’re elected to support to the bitter end.

Benjamin Ginsberg, a former general counsel to the Republican National Committee, recently wrote at Politico that the convention will not have the power to overwrite state delegate rules and the deadline for states to change their rules has passed. So there’s nothing to be done there.

But the convention will have the authority to do pretty much anything else it wants.

Who are these people?

Once Trump has failed to win a majority on the first ballot, who the actual delegates are could prove decisive.

As we have reported, many of the 2,472 will be local and state party officials as well as Republican volunteers. Not the sort of people you would expect to support Donald Trump, who after all wasn’t even a Republican until a few years ago and has repudiated many Republican Party policies, from the war in Iraq to health-care reform.

In most places, there is little the campaigns can do to influence the delegate selection process.

The majority is chosen at state conventions due to be held between April and early June. “Just over a quarter of the total delegates are picked directly by the candidates who win specific states,” writes Ginsberg.

The rest will be chosen by state conventions and executive committees.

Stealth delegates

Other campaigns, like Ted Cruz’, are trying to woo such local brokers and get their supporters elected as “stealth” delegates, ready to switch on the second ballot.

Trump, true to form, has done the opposite. “He has spit in the face of the national party and has publicly cast aspersions on state parties, too,” writes Marc Ambinder at The Week, “accusing them of stacking debate audiences with donors to favor his opponents.”

Rather than build relationships, the self-proclaimed dealmaker has “continually harassed and cajoled dozens of state chairs into staying silent,” one chairperson told Ambinder, “holding the loss of business relationships or donors over their heads.”

Such Sturm und Drang may play well with his angry voters, but it does not curry Trump any favors with flyover-country officials who, for all we know, could be planting bombs under his candidacy as we speak.