Donald Trump scored a decisive victory in Georgia’s March primary, taking more than half of the state’s 76 Republican delegates as part of a dominant showing throughout the South.

But the state party only binds delegates to support Trump for one ballot at this summer’s GOP national convention. That means any delegate may shift his or her support to any other GOP contender who might emerge if Trump can’t lock up the nomination before a second round of voting.

Preparing for that scenario, Ted Cruz supporters in Georgia want to secure as many of those spots as possible starting this Saturday.

Here’s a look at how the delegate selection process works:

WHAT DO DELEGATES DO?

Delegates from each state will attend the Republican National Convention in Cleveland from July 18 through 21.

Their primary role is choosing a presidential nominee. But they also will vote on rules for the convention process and discuss the national party’s platform. A total of 2,472 delegates get to vote at the convention — including the 76 from Georgia.

HOW ARE THEY CHOSEN?

More than half of Georgia’s delegates will be chosen Saturday at district-level conventions around the state. Each of Georgia’s 14 congressional districts selects three delegates, for a total of 42.

District leaders began sending instructions earlier this year about the application process, which tends to reward long-time or extensive involvement with Republican campaigns.

A total of 31 statewide delegates will be chosen in June at the state party’s convention in Augusta. This group often includes well-known officials and activists. In 2012, the list included Secretary of State Brian Kemp, Attorney General Sam Olens, House Speaker David Ralston, prominent tea party leader Julianne Thompson and Gov. Nathan Deal’s wife, Sandra Deal.

The only three delegates already determined are Republican National Committee members Randy Evans and Linda Herren and state GOP chairman John Padgett.

WHY AM I HEARING SO MUCH ABOUT DELEGATES THIS YEAR?

It’s rare for the party’s presidential nominee to remain mathematically undecided as the national convention begins. The last time it happened was 1976, when Gerald Ford lacked a majority heading into the convention. He ultimately won the nomination on the first vote over Ronald Reagan.

Trump hasn’t reached the threshold of 1,237 delegates required to lock up the nomination. His recent loss in Wisconsin narrowed the odds that the front-runner can do so before the July convention, increasing the stakes of delegate selection.

DO DELEGATES GET TO CHOOSE WHICH CANDIDATE TO SUPPORT?

Not during the first round, typically. Delegates are assigned to a candidate based on the March 1 primary results.

Georgia’s state party rules bind delegates to those results during the first round of voting at the convention, giving Trump 42 delegates, Cruz 18 and Marco Rubio 16.

After that, though, any delegate can change his or her vote. Also, quirks in both state law and convention rules could potentially free Rubio delegates to vote for another candidate from the very beginning.

SO ARE RUBIO DELEGATES STILL BOUND TO SUPPORT HIM OR NOT?

That’s still being debated, and likely won’t get settled until right before the convention opens.

Party rules differ between states, and the Georgia GOP would require 16 delegates to stick with Rubio on the first convention vote. But at least two things could override that rule, said Randy Evans, an Atlanta attorney, Georgia delegate and Republican National Committee member who sits on the convention Rules Committee.

First, Georgia state law says any delegates pledged to a presidential candidate who “withdraws” before the convention will be free to vote for another candidate. While Rubio suspended his campaign in March, attorneys disagree over whether that technically means he withdrew from the race, Evans said.

“We don’t have an answer to that yet,” Evans said. “It will be a big question mark as we move along.”

Also, GOP convention rules in 2012 allowed consideration only of candidates showing majority support from delegates in at least eight states. If the 2016 convention keeps that rule, Rubio delegates would be freed across the board.

HOW ARE THE TRUMP AND CRUZ CAMPAIGNS TRYING TO WIN DELEGATES?

Georgia political observers say the Cruz campaign has made a big push to earn delegate slots for supporters of the Texas senator. This weekend will test that effort.

Brant Frost V, the grassroots coordinator for Cruz in Georgia, said supporters are running for delegate spots in all 14 congressional districts in Saturday’s conventions. He also expects attendees of the state convention to closely scrutinize delegates elected there, going beyond name recognition.

“Campaigns don’t want just anybody going,” he said. “They want to make sure the people attending are strong supporters.”

Trump supporter Debbie Dooley acknowledged a slow start for the businessman in the delegate selection process. But Dooley, a tea party activist, said she’s confident that Trump supporters can catch up. Trump has hired Paul Manafort as his new delegate chief.

“The voters have spoken in Georgia, very loudly,” Dooley said. “That’s why it’s important who the delegates are.”