How Donald Trump Still Could Lose: What 'Is' a 'Contested Convention,' Anyway?

Winning popular vote in primaries doesn't necessarily hand Trump the GOP nomination

As it looks more and more like Donald Trump has the best shot at the Republican presidential nomination, some powerful parts of the GOP establishment are getting more and more nervous.

Their best shot at denying Trump the nomination is that "contested convention" you've been hearing about in the news lately. But getting there comes with another set of complications. PEOPLE breaks it down for you.

What is a contested convention?
Every election year, a party's nominee is chosen at the summertime convention. Typically, it's business as usual: One candidate has managed to secure the greatest number of delegates, or the number of delegates needed to win the nomination (for Republicans, that number is 1,237).

In a contested convention, also called a brokered convention, none of those vying for the party's bid manage to secure the number of delegates needed in primary and caucus voting. There are a few hundred delegates who are not promised to vote for a candidate. If they manage to bring a candidate's total up to the number needed in the first round of convention voting, then everything proceeds as usual. But if they don't, that's when a convention becomes brokered.

In that case, some states' delegates are no longer tied to casting their ballot based on the popular vote in some states and can change their choice. If that happens, the candidate who may have been closest to earning the delegate count can find his or herself losing a shot at the nomination. At times, the delegates can even look outside the original pool of a candidates for a nominee – giving the Republican establishment a chance to select one of their own, rather than Trump or Tea Party favorite Ted Cruz.

When is the last time there's been a contested convention?
It's been 40 years. The last time a Republican convention was held without a clear nominee from the get-go was in 1976, when Ronald Reagan challenged incumbent Gerald Ford. Ford was able to get the number he needed thanks to unpledged delegates, so the convention went on in a traditional manner. The Democrats had a similar situation in 1984, with Walter Mondale and Gary Hart, which also only lasted one round of voting and never made it to brokered status.

The last brokered Republican convention came in 1948 with three rounds of voting, eventually leading to the nomination of Thomas Dewey (and the defeat of Robert Taft).

It's important to remember that a brokered convention isn't a good sign for November: In all three of the aforementioned scenarios, the winning candidate came up short in the general election. So while a brokered convention may be the GOP's answer to avoiding a Trump nomination, it could come at a price for the party.

Could it happen this year?
Maybe. Even though Trump is winning, at his current pace, he's not winning quite enough delegates to put him on the path to securing the elusive 1,237 – but he's close, according to political website FiveThirtyEight.

Another factor is Rule 40, the new restriction which requires a candidate to have won a majority of delegates in at least eight primaries or caucuses to be considered at the convention. Donald Trump is the only candidate who meets this requirement thus far.

As for any major changes to try to avoid a Trump nomination, don't hold your breath. "I doubt any change is in the offing," Josh Putnam, a political scientist and founder of Frontloading HQ told CNN of the 1,237 delegate requirement. "I don't think they would either lower that or raise it in an effort to prevent Trump. That sort of proposal has never really come up."

What are the GOP bigwigs thinking?
Speaker of the House Paul Ryan has said he wouldn't take the nomination. John McCain has said that while he "disagrees with Mr. Trump on certain issues," he will support him if he's the nominee.

The most talk has come from 2012 Republican nominee Mitt Romney, who gave a speech pleading with his fellow Republicans to try to stop Trump, calling him a "fraud" and a "phony." But in said speech, he failed to endorse one of the remaining candidates, leading to murmurings that he would be open to accepting it himself.

And Republican strategist Mark Pfeifle of OTR Strategies told PEOPLE: "The ‘never-Trump' Republicans don't want to hear it but the reality is that Republicans are, at some point, going to have to realize that it's a Trump nomination. The only question is when."

Who would the nominee be after a contested convention?
If some in the GOP establishment have their way, it wouldn't be Cruz or Trump. At first, it really all depends on the unpledged delegates, and if they're unable to bring one candidate past the mandated margin, then things are a little more up in the air. There's even been discussion that the delegates would look to an outsider – someone who hasn't yet thrown his or her hat in the ring for the 2016 bid.

And what the man himself has to say about the whole thing? If Trump is denied the nomination despite winning the popular vote, he predicts "riots" will take place.