After winning the April 5 Wisconsin primary, Ted Cruz appeared to reach out to the GOP establishment – and ask for its trust. (Peter Stevenson/The Washington Post)

Iowa and New Hampshire voted first in the presidential election this year. New York and California are where candidates can win the largest number of delegates.

But if the Republican presidential race between Donald Trump and Ted Cruz is decided by just a handful of delegates, what happens in Colorado this weekend might matter most of all.

Colorado is one of six states or territories — including American Samoa, Guam, North Dakota, Wyoming and the Virgin Islands — that opted not to hold Republican presidential caucuses or a primary decided by voters. Instead, the state’s Republicans are meeting this weekend to finalize a slate of 37 delegates to the Republican National Convention in Cleveland in July.

The process is not simple, however. On Saturday, thousands will pack an arena in Colorado Springs as more than 600 candidates speak for 20 seconds each in an effort to be delegates. Cruz is also slated to speak, along with a representative for the third GOP presidential candidate, Ohio Gov. John Kasich.

“It’s going to be messy,” said George Leing, who is already guaranteed a delegate spot as a state committeeman for the Republican National Committee. “It’s not the prettiest thing, but so far it’s working.”

This summer's political conventions could get heated – but it certainly wouldn't be the first time. (Peter Stevenson/The Washington Post)

Unlike other states where campaigns spent millions of dollars on rallies and television commercials, winning support in Colorado requires more time-consuming, arduous effort that leads to people like Kendal Unruh.

The anti-abortion activist from Castle Rock, Colo., has attended seven Republican national conventions and has helped write the party’s official platform. This year, Unruh is organizing a slate of like-minded, anti-abortion activists to run for Colorado delegate slots. Their main goal is to ensure that the GOP maintains its staunch anti-abortion position. Her second goal is to elect Cruz as president.

“Senator Cruz isn’t just doing his homework by devoting time and resources to the meticulous process of winning over delegates, but by his record he’s winning these people over by being a lifelong, consistent conservative,” Unruh said. “That is something that money can’t buy. That is something that winning debates can’t buy.”

In February, Colorado Republicans began meeting at the precinct, district and county levels to select candidates to run for delegate seats. Party faithful are gathering this week to elect three delegates for each of its seven congressional districts. Thirteen more statewide delegates will be chosen Saturday.

Anyone seeking a delegate slot has the option of declaring a preference in advance or running as part of a slate of like-minded candidates such as the ones organized by Unruh and others. Pledged delegates who win must vote for their preferred candidate on the first ballot at the national convention. “Unpledged” delegates have until votes are cast in Cleveland to make a decision. If the race remains unsettled, unpledged delegates will become some of the most sought-after Republicans in the country as Cruz, Trump and Kasich seek to win them over.

“We have a lot of people coming out of the woodwork,” said Amy Stephens, a former Colorado House majority leader who is supporting Kasich and helping organize slates of his supporters to win delegate slots.

Colorado GOP leaders decided not to hold presidential caucuses this year, citing the costs and potentially chaotic nature of the contest. Many party members disagreed, thinking that the party was surrendering any chance of influencing the outcome.

Jimmy Sengenberger, a 25-year-old conservative radio talk-show host in Denver who is running as a pledged delegate for Cruz, initially balked at the decision not to hold caucuses. “Now it seems perfect,” he said. “If there’s any cycle in which the party should do it this way in Colorado, this is the year.”

Gregory Carlson, 27, is typical of the kind of politicos who turn out for state conventions. He’s studying to become a professional parliamentarian. He’s read Robert’s Rules of Order cover to cover — twice.

Carlson is running as an unpledged delegate and says he would seek to ensure that only declared presidential candidates are considered for the nomination in Cleveland. “If we’re going to nominate someone who hasn’t been on the debate stage, it’s a disservice to the other candidates and their supporters,” he said. “Why pick somebody different at the finish line?”

Leing is also remaining unpledged, citing his party leadership role. “I don’t want to see any gaming of the system to see one campaign try to favor a particularly candidate,” he said.

Trump is leading the GOP delegate race and continues to lead polls nationwide. But he lost badly to Cruz in Wisconsin on Tuesday, and his team is struggling to master the complex delegate rules. In Louisiana, Cruz’s campaign exploited party rules to pack the delegation with supporters even though Trump won the state handily. Cruz also won a majority of the 28 delegates elected at North Dakota’s GOP convention last weekend. Trump has accused Tennessee Republicans of robbing him of his fair share of delegates.

In Colorado, Cruz is scheduled to make a final sales pitch, and Kasich is sending former senator John E. Sununu of New Hampshire to speak on his behalf. Trump will not be attending, according to the state GOP.

“It’s always been difficult to parachute into these conventions and expect them to go your way,” Sununu said, adding that the complicated nature of selecting delegates “shouldn’t be a surprise to anyone.”

Regina Thompson, Cruz’s Colorado coordinator, agreed.

“A contested convention is the process,” she said. “It should not rip the party apart. This has been the process of the Republican Party for 160 years or so. It’s not stealing it from anyone; it’s not dirty tricks. This has simply always been the rules.”