Republicans are in uncharted territory as they inch toward their first contested presidential nominating convention in 40 years.

Delegates to the quadrennial GOP gathering cast the official votes that nominate the party's presidential candidate. But not since Ronald Reagan challenged President Gerald Ford in Kansas City have their votes been more than a formality. This year could be different, as four Republican contenders threaten to divide the vote in the primaries and caucuses and arrive in Cleveland having blocked each other from 1,237 delegates, the threshold needed to secure the nomination.

"These people will be free to vote for who they want to," said Shawn Steel, who as the Republican National Committeeman from California is a delegate to the party's July convention. "These are political people. When they realize the power they have, there is going to be a lot of dealing."

The looming question is whether delegates are prepared to exercise that power and nominate a candidate other than the individual who earns a plurality of votes (and delegates) in the primaries.

It's an issue not just because of the uncertainty of the outcome, but because Donald Trump is the clear front-runner. The New York celebrity businessman is not a traditional Republican. He has historically supported liberal politicians and causes, and despite evolving on some issues still holds many positions that are anathema to the GOP and its conservative underpinnings. There's a movement among some Republicans and conservative activists to block Trump from the nomination.

A growing number of elected officials are declaring they will not vote for Trump in November. Joining them are insurgents who are normally at odds with the GOP establishment.

Fear of Trump could motivate convention delegates to use the rules to nominate another candidate, if the reality television star falls short of 1,237. His remaining competitors include Sen. Ted Cruz of Texas, Ohio Gov. John Kasich and Sen. Marco Rubio of Florida.

"I think that is what is largely driving the conversation," said Ryan Call, the former chairman of the Colorado Republican Party. "If you had Cruz in the lead in terms of delegates, I don't think you'd have this conversation in an ongoing way."

Current and former Republican officials caution that a contested convention, and the factors that could impact how it plays out, are more complicated than many people realize.

The week before the convention, the convention rules committee — comprised of about 100 delegates, two representing each state — will meet in Cleveland to hash out and vote on the rules of the gathering.

It's similar to how the House Rules Committee votes on a set of rules that govern the rules for debating and voting on legislative proposals. Normally, the presumptive nominee would oversee the proceedings, pushing for rules that it wants implemented for the four-day convention.

In the event of a contested convention, the main competitors for the delegate vote are likely to engage in intense lobbying of rules committee delegates, to pass a rules package that makes it easier to win the nomination during a floor vote of convention delegates.

"If you control the rules committee, you control the convention. That's what Ford did in '76," a veteran Republican operative said.

Then there's the issue of who the delegates are. In 2012, after Mitt Romney finally eliminated former Sen. Rick Santorum and became the presumptive nominee, his campaign invested considerable time, money and personnel toward electing convention delegates, and alternates, that supported the former Massachusetts governor. The RNC collaborated with Romney to help ensure a smooth convention that wasn't riled by rogue votes, in particular for rival candidate Ron Paul.

With the convention just four months away and the nomination still in play, it's unclear if any of the campaigns have the time, resources and expertise to focus on delegate elections. The RNC certainly can't play favorites absent a candidate getting to 1,237.

"It isn't enough to bank on the Trump delegates flipping to someone else after the first round of balloting, you have to make sure your people are elected," a GOP strategist involved in the Romney-Paul delegate battle said. "That's a monstrous lift and I'm not sure how any of the campaigns could do that and continue to still run to win delegates."

Republican officials concede that a true contested convention is now possible. Exactly how the proceedings would unfold is hard to predict, given that the rules have yet to be determined. But even some rules that are assumed to govern the 2016 convention are in dispute, creating yet another level of unpredictability to what might happen.

For instance, some veteran delegates and Republican National Committee members dispute that party rules bind the delegate votes to the winner of the states they represent on the first ballot, as the RNC has said and is widely thought.

Curly Haugland, the Republican National Committeeman from North Dakota and a member of the RNC rules committee, said there is nothing in the rules that require a delegate to support any candidate during the first roll call vote on the convention floor. Haugland said that a fine-print reading of the Republican Party rules as adopted in Tampa in 2012 actually undermines the idea that the candidates are winning any delegates in the primaries and caucuses.

Since 1980, it hasn't mattered, because the GOP always ended up with a presumptive nominee before the convention and there were no candidates running to challenge that candidate in a floor vote of the delegates. But given the unusual nature of this contest, delegates committed to exercising the power could upend a nominating convention that has become nothing more than a made-for-television formality.

"This convention is going to play out by the rules. I'm pretty convinced of it," Haugland said.