With every primary vote over the last several months, the Republican candidates for president have inched closer to the nomination finish line: the GOP national convention. But, unlike in prior election years, the 2016 Republican National Convention could quickly become just as dramatic and chaotic as this season’s primary race. And, for the first time in more than a generation, voters might have to familiarize themselves with a new term: a brokered convention. But just what is a brokered convention? At this point, it could be the Republican establishment’s last chance to defect against their party’s leading candidate.

It’s no secret that Republican leaders have been less-than-pleased over billionaire businessman Donald Trump’s series of victories over more palatable candidates like Texas Sen. Ted Cruz and former Florida Gov. Jeb Bush (who ended his lackluster bid for president in February). But, Trump’s enigmatic popularity among primary voters and his talent for drowning out the competition on nearly every form of media have made a Trump nomination victory almost certain.

To earn the party nomination, a Republican candidate must win at least 1,237 delegates of the 2,472 available delegates, according to USA Today. And while neither Cruz nor Ohio Gov. John Kasich have a chance at overtaking the 739 delegates that Donald Trump has amassed so far, if they managed to stop the front runner from reaching that magic number, the convention rules allow for a possible challenge to the Trump juggernaut.

But will the GOP face an open, contested, or brokered convention? According to a PBS report, the different terms all essentially point to the same scenario: without a single GOP candidate claiming a majority of delegates, the doors open for the party to present other candidates for the party nomination — even if that candidate has never won a single vote in the primary race.

The difference is one of timing: when it’s clear that no single candidate will claim a majority of delegates to earn the nomination outright, the convention is considered "contested" or "open." And, according to the PBS report, open or contested conventions aren’t all that rare: the Republican party has had 10 since its first convention back in 1856. The GOP’s last contested convention was in 1976 when both Gerald Ford and Ronald Reagan came close to the magic 1,237 number, but neither was able to secure a clear victory.

But a brokered convention is a far less common scenario. The party convention would enter brokered territory if none of the candidates are able to secure the nomination after the first round of voting, according to USA Today. That’s when the drama could really begin in what USA Today described in a separate story as “pure chaos”:

Multiple ballots, rules fights, floor demonstrations, dark horses and favorite sons — just like an old-time convention, except for smoke-filled rooms.

What happens after that first vote isn't exactly set in stone. A second ballot would have to be taken, according to USA Today, and that's where the actual process gets fuzzy with delegate negotiations and floor fights. There's even been speculation that the establishment leaders could throw support behind a candidate who isn't currently in the running — names of party favorites like Mitt Romney and House Speaker Paul Ryan have been thrown out as possibilities. And party leaders could scrap the convention rule that might bar them from doing that, which only adds to possibility for confusion and chaos. In short, a brokered convention would be exciting to watch, but a nightmare to manage.

According to PBS, the GOP hasn’t seen a brokered convention since 1952, when Dwight Eisenhower arrived at the finish line with just 26 percent of the total delegates, but defeated Ohio Sen. Robert Taft after a series of heated rounds of votes.

Whether voters — and viewers — will be in for drama in Cleveland this July remains to be seen. If his high levels of voter support continue in the remaining races, Trump could secure a mathematical win over his rivals and close the door to a contested convention altogether, the New York Times recently reported. But barring that, a little-used provision in the party convention rules could be the only way forward for those seeking to stop the front-runner in his tracks.