Strong showing from all our counties! You are all awesome. #MEGOPSC2016 #mepolitics pic.twitter.com/ZjddkE4VTc

— Maine GOP (@mainegop) April 22, 2016

Meanwhile, the secretive Contests Committee met behind closed doors. The party won’t even release the names of its members yet. But come mid-June, when skirmishing in advance of a possible contested convention will be at its height, the nine-member body will be at the center of the battle.

This is because the Contests Committee is the first stop in changing delegate counts post facto. It can, based on its view of irregularities in the selection process, advise that entire slates of delegates be sent home, expunging them from a candidate’s total. It’s where Donald Trump’s charges of unfairness in the delegation selection process will first be litigated. If Trump falls short of the 1,237 delegates needed to secure the presidential nomination, those delegate complaints, often referred to as “credentials challenges,” could be part of the New York mogul’s playbook for beating Ted Cruz on a second or third convention ballot.

If needed, the Contests Committee issues opinions on the delegate selection proceedings at events like the state GOP convention in Maine, which begins Friday. At Maine’s 2012 GOP convention, Mitt Romney forces, aided by a Contests Committee recommendation on supposed balloting irregularities, discounted a slate of Ron Paul delegates-about half of the state’s entire delegation-even though Paul had won 21 out of 23 delegate slots. “From my experience with the process, it does seem to me that the facts of the case are far less important than who’s in the position to make the decision,” said Eric Brakey, a 2012 Maine delegate who was sent home shortly after arriving in Tampa.

The campaigns’ preparations for this struggle are already well underway. This week, Paul Manafort, a veteran political operative who Trump recruited this month partly because of Manafort’s contested-convention experience-he worked for Gerald Ford’s campaign in 1976-hired William McGinley, a Republican political attorney, to advise the campaign on possible challenges to the credentials of delegates.

“We’ll be filing protests,” Manafort said Sunday in an interview with ABC’s This Week. “Missouri, we’re going to be filing protests. Colorado, we’re going to be filing protests.”

The process by which national delegates are selected at local caucuses and conventions is a gauntlet of thorny bureaucratic hurdles that make clerical and procedural errors easy to make, especially in election years that draw first-time activists. The legitimacy of delegates can be challenged for any number of reasons, but most arise from voting irregularities at the state conventions-sloppy paperwork, miscounted ballots, a chair who ignores the rules, or any reason to doubt that people in the room selecting delegates were authorized to be there.

“We did dozens of interviews, going back to previous caucus and conventions to learn what happened, so we could have a process that is iron clad,” said Jason Savage, the executive director of the Maine GOP.

This year, states have to certify their delegates by June 13. All challenges must be filed with the RNC five days later, allowing the Cruz and Trump campaigns to see how the rest of the contest shakes out before starting legal proceedings. The RNC Contests Committee’s delegate recommendations will be considered in July by a convention credentials committee, made up of two delegates from each state and territory, the week before Cleveland. Whichever candidate has the most delegates on this committee will have the advantage, but ultimately, the final decision is made by a full convention floor vote.

Since challenges often result from human error, the states most susceptible to credentials challenges are those that do not hold statewide primaries, but instead make their presidential picks through more chaotic and unpredictable caucuses or conventions. There are 16 such states and territories, with more than 400 delegates between them. Trump has only won four, half as many as Cruz, making them ripe for challenges that could benefit the front-runner.

Credentialing fights have shaped presidential races before. At the 1952 Republican convention, neither Dwight Eisenhower or Robert Taft walked in with enough delegates to clinch the nomination. Eisenhower’s campaign, however, had challenged Taft’s delegates in several states. A convention-floor rules battle eventually blocked those questioned delegates from voting on their own credentials, ensuring an Eisenhower victory.

In 2012, Maine was one of several states where delegates were challenged, but it was by far the most dramatic. The trouble started when Paul’s campaign elected one of their supporters as chair of the state convention, frustrating state party leaders and the Romney campaign. From there, a series of floor fights and balloting problems dragged on throughout the convention. The complaint that booted Brakey and others from Tampa cited problems with lax floor security, ballot counting confusion, and concerns about an absence of a quorum when certain votes were taken. “One delegate was surprised to see someone wearing his wife’s credentials at the Convention, considering his wife never came to the convention,” said Romney’s campaign challenge, which was upheld by an RNC Contests Committee and the national convention’s Committee on Credentials.

In the end, 10 pro-Paul delegates, who had already booked airfare and hotel accommodations on their own dime, were replaced with Romney supporters, a decision that led Maine Governor Paul LePage to boycott the convention in protest.

Now the convention, starting Friday at the Cross Insurance Center in Bangor, is expected to be a struggle between Trump and Cruz. LePage was an early Trump endorser, and retains significant sway in the state’s politics. But Cruz has flexed more organizational muscles on the ground-he won the state caucuses on March 5 with about 46 percent the vote, giving him 12 of the state’s 23 delegates on the first ballot. Nine will vote for Trump; two go to Ohio Governor John Kasich for finishing third. A couple hundred people are expected to seek delegate positions for 20 spots this weekend in a fight that will pit grassroots verses the governor.

“People have their own convictions and the traditional coalitions haven’t really coalesced like they normally would,” said Savage, nodding to an air of unpredictability at the convention. “But if there’s one thing you can count on is people listen to the governor.”

Former rivals-turned-surrogates will be on hand. Carly Fiorina will be speaking from the convention stage for Cruz, and Trump supporter Ben Carson will give the keynote speech Friday night.

“I expect it will be pretty drama filled, as it has been in the past,” said Lance Dutson, a GOP strategist in the state. “The stakes are higher. It could be quite a show.”

Trump’s rage at the delegate-selection process-the “rigged system,” in his words-has been a prominent feature of his campaign in the past month. The Contests Committee will be where he first seeks redress.

“Post-New York primary, we’re more confident than ever that we’ll win on the first ballot, but we are going to keep our options open on these challenges,” said Barry Bennett, a senior adviser to the Trump campaign, who said if Trump reaches 1,237 delegates then there’s no need to bother filing challenges. “We haven’t made any decisions yet, but we certainly have some legitimate beefs.”

In March, Trump threatened to lodge a formal complaint with the RNC over the delegate allocation process in Louisiana, where he won the popular vote but was out-hustled at the state convention by the Cruz campaign, which may receive more delegates than Trump in the state. Bennett said Trump’s team was left out of a closed meeting to select delegates to the convention committees that will write the party rules before Cleveland.

In Colorado, which held its convention earlier this month, Trump’s campaign blamed the state party for ballot misprints, among other issues, that they said made electing their delegates more difficult. Since Cruz won most of the delegates in Colorado, any changes to the slate would favor Trump.

“Whenever you have a contest as uncertain as this one is, it would be surprising if there weren’t procedural disagreements and arguments that rules were not being adhered to,” said Thomas Balch, a parliamentarian who served at Maine’s 2012 state convention. This year, he’s been advising local party leaders on how to bulletproof their conventions so that delegations don’t get caught in the political crossfire.

Last weekend, Balch served as a parliamentarian at Virginia’s 10th Congressional District convention, where eight local delegates were deemed ineligible to move on to the national convention because they had supported independent candidates in a previous election, which under party rules disqualifies them from being a Republican delegate for a period of time.

“I was specifically told by the [convention] chair that in other years when it was clear who the nominee was going to be, they would have probably not been as rigorous in enforcing the rules,” Balch said. “But this year, it was specifically important to make sure that every thing was done in accordance of the rules out of fear of a challenge.”

Balch said parliamentarians are in high demand everywhere this cycle, as campaigns and party leaders look for someone to review local and state delegate selection meetings for any sign that rules had been violated. “It’s extremely easy to make mistakes,” he said. “If you don’t know the rules, someone who does can run circles around you.”

-With assistance from John McCormick and Jennifer Jacobs.