Supporters listen as Republican presidential candidate Donald Trump speaks at a campaign rally on Wednesday in Bethpage, N.Y. (Jabin Botsford/The Washington Post)

West Virginia looks perfect for Donald Trump: a struggling working-class state filled with the types of voters who have backed him elsewhere and could deliver one of his biggest victories.

But a sweep there might not matter. That’s because as many as 34 delegates — the entire contingent — may be free to back whomever they want at the Republican National Convention.

Much the same is true in Pennsylvania, home to a hotly contested April 26 primary, where there are 54 uncommitted delegates. Other states and territories, from Colorado to Wyoming to Guam, will also send squads of unbound representatives.

These are the swing voters of the GOP nominating contest, nearly 200 activists and elected leaders beholden to nothing except their personal judgment and empowered to make or break candidacies.

If Trump arrives at the July convention in Cleveland just shy of the 1,237 delegates required to secure the nomination outright, these unbound delegates could decide to push him over the top — or force a contested convention with successive rounds of balloting.

Donald Trump will almost certainly be the delegate leader heading into July's Republican National Convention – but that doesn't mean he'll win the nomination outright. (Peter Stevenson/The Washington Post)

“It’s the wildcatter of delegate selection,” said Ed Brookover, a senior adviser to Trump, who drew an analogy to risk-taking oilmen who drill in unexplored land.

The three remaining candidates are identifying these delegates, researching their proclivities and beginning to cajole them. The law surrounding them is so unclear that Trump could conceivably fly them to Florida for a weekend of luxuriating at Mar-a-Lago, his gold-adorned and palm-lined private club — where, naturally, they could be subjected to personal lobbying to support Trump.

Brookover did not rule out the Trump campaign entertaining delegates at one of Trump’s properties or paying for their travel costs to Cleveland. But he added: “You certainly can’t offer anything which would be considered a bribe. We can’t give them $100,000.”

Charlie Black, who is helping lead Ohio Gov. John Kasich’s delegate strategy, recalled working on Ronald Reagan’s insurgent campaign in 1976 and struggling to court delegates as industriously as then-President Gerald Ford.

“People got to stay at the White House, fly on Air Force One and meet Queen Elizabeth,” Black said.

Federal rules do not provide clear guidance about whether delegates can accept items of value from a campaign, other than reimbursement for their travel expenses. Campaign finance lawyers are divided over whether federal or state anti-bribery statutes would apply to delegates who are not elected officials — and if so, what kinds of perks or inducements could be illegal.

After being outmaneuvered on several early delegate plays by Sen. Ted Cruz of Texas, his main rival, Trump is getting up to speed on the complicated process. On Thursday, he announced that power to oversee all activities related to the convention and delegates activities would be consolidated under Paul Manafort, a newly hired adviser.

“These unbound delegates are important because they could deny Trump any opportunity to get over the magic number on the first ballot — or they could also push him over the top,” said Jason Osborne, a GOP operative versed in convention procedures who advised Trump’s campaign earlier this year but currently is unaffiliated.

By contrast, Cruz has been preparing for this stage of the race for more than a year, his advisers said. The Cruz campaign has methodically recruited supporters to run as unbound delegates in places such as Pennsylvania and West Virginia and plans an intense push to persuade those who will have a vote on the convention floor.

In Colorado, Cruz has picked up at least 18 delegates this week and could sweep the state’s total slate of 37 at its state convention on Saturday. Volunteers in Colorado have been organizing for Cruz since last summer.

“We’re understanding every delegate in the country, tracking them, understanding where they came from, what their interests are,” said Saul Anuzis, a former Republican National Committee member who is helping the Cruz campaign on delegate outreach.

The arcane rules governing the nominating process mean that in Pennsylvania, a populous state that all three remaining candidates are targeting, the winner will automatically receive only 17 of the state’s 71 total delegates. The other 54 delegates, who are elected on the primary ballot in congressional districts, will be unbound.

“Even if you stood up and said, ‘I’m for Governor John Kasich’ and your district duly elected you based on your word, you can go to the convention and say, ‘Nope, I changed my mind,’ ” Brookover said.

Phil English, a past delegate from Pennsylvania and a former congressman, is among the 162 Republicans running to become delegates. He said he considers himself “a free agent” and is open to nominating someone not currently campaigning, such as House Speaker Paul D. Ryan (R-Wis.).

“I intend to listen to people in my community, look at how they vote in the beauty contest, and then make my own assessment of what would be the strongest ticket for the Republican Party,” English said.

The Pittsburgh Tribune-Review recently surveyed Pennsylvania’s delegate candidates and found that 61 of the 110 respondents said they would cast at least their first ballot for the presidential candidate who wins the state’s primary. Thirty-two of the respondents said they already are committed to a candidate, while the remainder were undecided.

“They, in effect, become the Republican Party’s superdelegates, just like the Democrats have,” Anuzis said, referring to the hundreds of delegate slots on the Democratic side not chosen by voters. “They could do whatever they want to do.”

Many delegates have been active in their state parties for years, so the campaigns have tasked local surrogates — such as former Pennsylvania governor Tom Ridge on Kasich’s behalf — to help make personal appeals.

For instance, Brookover said, if a delegate cares about the issue of religious liberty, he or she may get a call from Liberty University President Jerry Falwell Jr. vouching for Trump.

Delegates could be persuaded more than regular voters by ­process-oriented political arguments. “Primary voters don’t care about electability,” Black said. “But delegates do care about it. . . . They want to elect a president, but they also want to save their senators, their congressmen and Republicans down the ballot.”

First, though, the delegates have to be selected. In West Virginia, that means winnowing a field of more than 300 to 31 open slots, which will happen during the May 10 primary. Some delegate hopefuls run aligned with a presidential candidate, meaning they must vote for that candidate in the first ballot at the convention, while others run as uncommitted.

The Trump campaign recently opened an office in Charleston and is trying to persuade more delegate candidates to commit to Trump. Allies are arguing that Trump would be best to guide coal country out of its chronic economic despair.

“In the last 48 hours, some of our candidates for delegates to the national convention have been called by the Trump folks,” said Kris Warner, an RNC member from West Virginia. “They’re leaning pretty heavily on folks.”

Matea Gold in Washington and Ed O’Keefe in Colorado Springs, Colo., contributed to this report.

Correction: An earlier version of this story misstated the number of unbound delegates in Pennsylvania.