Colorado will not vote for a Republican candidate for president at its 2016 caucus after party leaders approved a little-noticed shift that may diminish the state’s clout in the most open nomination contest in the modern era.

The GOP executive committee has voted to cancel the traditional presidential preference poll after the national party changed its rules to require a state’s delegates to support the candidate that wins the caucus vote.

The move makes Colorado the only state so far to forfeit a role in the early nomination process, according to political experts, but other caucus states are still considering how to adapt to the new rule.

“It takes Colorado completely off the map” in the primary season, said Ryan Call, a former state GOP chairman.

Republicans still will hold precinct caucus meetings in early 2016 to begin the process of selecting delegates for the national convention — but the 37 delegates are not pledged to any specific candidate.

The Democratic Party still will hold a presidential straw poll March 1 — a Super Tuesday vote in a key swing state that is attracting attention from top-tier candidates.

For Republicans, no declared winner means the caucus will lack much of its hype. The presidential campaigns still may try to win delegate slots for their supporters, but experts say the move makes it less likely that candidates will visit Colorado to court voters.

The Colorado system often favors anti-establishment candidates who draw a dedicated following among activists — as evidenced by Rick Santorum’s victory in 2012 caucus. So the party’s move may hurt GOP contenders such as Donald Trump, Ben Carson and Rand Paul, who would have received a boost if they won the state.

State Republican Party Chairman Steve House said the party’s 24-member executive committee made the unanimous decision Friday — six members were absent — to skip the preference poll.

The move, he said, would give Colorado delegates the freedom to support any candidate eligible at the Cleveland convention in July. Republican National Committee officials confirmed that the change complies with party rules.

“If we do a binding presidential preference poll, we would then pledge our delegates … and the candidates we bind them to may not be in the race by the time we get to the convention,” House said in an interview Tuesday.

The caucus is likely to occur in February, but party officials will meet next month to finalize the date.

In 2008 and 2012, die-hard Republican voters gathered at caucus meetings to begin the delegate-selection process of selecting delegates to the national convention and voice support for presidential candidates in a straw poll.

The votes, however, didn’t require Colorado delegates to support any particular candidate at the national conventions. This allowed for delegates that supported a losing candidate to vote for the nominee and demonstrate party unity at the convention.

But the freedom also opened the door for political mischief, as Colorado saw in 2012 when Ron Paul supporters managed to win a significant portion of the delegate slots, even though Paul finished far behind other candidates in the Colorado caucuses.

The RNC tightened the rules in 2012 to eliminate nonbinding straw polls and help prevent similar stunts in the future, forcing Colorado Republicans to re-evaluate their process. An effort earlier this year to switch to a presidential primary system failed amid party infighting.

“It’s an odd scenario,” said Josh Putnam, a political science lecturer at the University of Georgia who runs a popular blog on the presidential nominating process. “It’s not to say the campaigns won’t be there. … But you won’t have a good reflection of support at the caucuses, much less Colorado Republicans as a whole.”

Other caucus states are grappling with the rule change in different ways as they finalize their plans before the deadline at the end of September, Putnam said, but he is not aware of any state that has abandoned the presidential caucus vote.

With the change, the only way Colorado Republican delegates would remain relevant is the remote chance that no candidate emerges as a clear winner in the primary contest. In this case, the state’s unbound delegates would receive significant attention and may hold the key to victory in a floor fight.

“If there’s the potential for a brokered convention in any way, the unaffiliated delegates become extremely important,” said Joy Hoffman, the Arapahoe County GOP chairwoman who attended the party meeting. “If there is someone who becomes a front-runner, … then nobody’s important. So I think the view became that if we were not bound, it’s not the worse thing that could happen.”

John Frank: 303-954-2409, jfrank@denverpost.com or twitter.com/ByJohnFrank