There will be 2,472 Republican delegates going to Cleveland for the national convention, with 1,237 needed for a candidate to secure the nomination -- but those intent on blocking Donald Trump are focused on a much more manageable number: 57.

That figure is 50 percent plus one of the 112-member Convention Rules Committee, the group with the power to end Trump’s grip on the GOP nomination. A victory there, said the leader of the “Free the Delegates” group on a Sunday night conference call, and it would be all downhill.

“Once it passes Rules … it’s just kind of an easy sell,” said Kendal Unruh, a delegate from Colorado, who predicted that with the committee’s approval, winning over a majority of the full convention would be easy. “They’re not going to be putting up strong resistance to this.”

Trump’s campaign did not respond to a Huffington Post query about Unruh’s new group. Trump himself has called the plan “illegal” -- although Supreme Court rulings suggest it is perfectly legal -- and a “hoax” by the media.

Unruh is a high school history teacher at a Christian school in suburban Denver. She supported Cruz during the primaries, and a week ago became the latest in a line of Republicans working to keep the nomination from the reality TV star.

Conference call organizers said some 1,000 people participated in the call, up from 30 or so on last week’s, including “hundreds” of delegates and alternates. They announced a new website, freethedelegates2016.com, and urged Republicans around the country to contact their states’ convention delegates for their support.

Unruh specifically will be asking the Convention Rules Committee, of which she is a member, to pass a “conscience” clause to let delegates out of their obligation to vote for the winner of their state or congressional district. She said that because many Republicans are by their nature “rule-followers,” they would be grateful for “a permission slip” to let them off the hook. She said she was heartened by House Speaker Paul Ryan’s remarks to NBC on Sunday that he wouldn’t be telling delegates what to do.

“They write the rules. They make their decisions,” said Ryan, who as chair of the convention will hold extraordinary power over its actions. “The last thing I would do is tell anybody to do something that's contrary to their conscience. Of course I wouldn't do that.”

Unruh and her supporters, though, face a hard reality: Ryan, like many party leaders, has endorsed Trump. He will enter Cleveland with 1,457 delegates “bound” to vote for him through at least the first ballot. And top Republicans warn that taking the nomination from Trump will be far worse for the party than losing the presidency in November.

Iowa state party chairman Jeff Kaufmann called the new attempt naïve and hypocritical for trying to undo the will of Republican voters. “The people have spoken in overwhelming number,” he said. “If they pull off what they say they will, we will not have a party. Period."

The Republican National Committee’s chief strategist, Sean Spicer, called Unruh’s efforts “silly” in a statement late last week. “There is no organized effort, strategy or leader of this so-called movement. It is nothing more than a media creation and a series of tweets,” he said.

And a longtime member of the RNC who will also serve on the Convention Rules Committee said privately that Unruh’s plan is too little and too late. “I don't think anything happens. It's over. He won,” he said of Trump.

Republican Party members’ angst about Trump has only gotten more acute in recent weeks. Trump’s fundraising has been sluggish, he has allowed Democrats to outspend him by tens of millions of dollars in advertising in key swing states, and he has shown little interest in building an organized voter-turnout effort.

Most baffling of all, said Texas GOP consultant Matt Mackowiak, is his preference for staging rallies in places like Texas -- certain to vote Republican in November-- and California -- equally certain to vote Democratic -- rather than the 10 or so states that will actually decide the outcome.

In the hours he wastes performing those, Trump could be on the phone, making fundraising calls or encouraging volunteer organizers. “Even if he's just taking a nap and getting recharged, that's probably a better use of his time,” Mackowiak said. “The last four weeks have been disastrous."

Still, Republicans are probably better off trying to persuade Trump to drop out than taking the nomination away from him, because doing so would alienate the millions who voted for him this spring.

“It risks losing this base of support Trump has, if not forever, then at least for this election cycle,” Mackowiak said, adding that as bad as Trump’s performance and polling have been, they’re not bad enough yet for party leaders to actively dump him. “I don't know if there's enough evidence for skittish Republican leaders to take a bold stand.”

Editor's note: Donald Trump regularly incites political violence and is a serial liar, rampant xenophobe, racist, misogynist and birther who has repeatedly pledged to ban all Muslims -- 1.6 billion members of an entire religion -- from entering the U.S.