So much for the anti-Trumpers' daring "vote your conscience" movement.

The Great Convention Revolt of 2016, to be staged at the Republican National Convention (RNC) in Cleveland, was supposed to block Donald Trump's path to the party's nomination for president.

But the much-discussed dump Trump scheme to unbind delegate votes apparently drew its final breath last night, before being crushed by the RNC's powerful standing committee on rules.

Maybe it just wasn't meant to be. Not that Free the Delegates, the grassroots organization spearheading the mission, didn't try their damnedest.

The coalition had for months been staging a revolt to float a convention rule challenge — one that was buoying #NeverTrump conservatives in the lead-up to next week's July 18 convention in Cleveland. It was called the "conscience clause."

Rules Commitee

Republicans on the 112-member standing committee on rules at the Republican National Convention in Cleveland. (C-SPAN)

At 9:48 p.m. on Thursday, a day sooner than expected, it was soundly defeated in a vote by the convention's rules committee.

"Clearly, the nays have it," Enid Mickelsen, who chairs the rules committee, declared, dismissing the need for a standing vote on the matter.

"We're going to move forward."

Later, Iowa Republican national committeeman Steve Scheffler addressed the Free the Delegates contingent, urging them to drop their cause once and for all.

"It's over, folks," he said. "We need to get behind our candidate."

The "vote your conscience" campaign had sought to revoke a rule binding delegates to vote for candidates based on the winner of their state primary or caucus. Had it succeeded in Cleveland, it would have untethered delegates who, under current guidelines, are committed — even if reluctantly — to backing a certain vainglorious New York billionaire.

"Conscience voters" were primed and ready to throw a dash of suspense into the proceedings. They were convinced their proposal to insert new language into Rule 38, a tweak to allow voters to back anyone they wished to support, would be met with support from the 112-member rules committee.

When it came time for the actual vote, the vocal Trump resisters failed to muster enough noise to make an impact.

'It would be devastating to the party to overturn the results of the nomination process — far more damaging than if Trump would run and do poorly.' - Longtime Republican national committeeman Morton Blackwell

Longtime convention insiders like Morton Blackwell expected this result. He viewed the unbinding efforts as a Hail Mary play, anyway.

'It's not dead'

"A fantasy," the rules expert said of the scenario. "It would be devastating to the party to overturn the results of the nomination process — far more damaging than if Trump would run and do poorly."

As for what would happen if a delegate declares a vote that conflicts with a state's binding election result? Blackwell said the current rules were always clear: "The secretary of the convention is instructed to ignore it" and record instead the votes as allocated by the binding primary.

Kendal Unruh

Kendal Unruh, founder of the anti-Trump coalition Free the Delegates, presents her proposed amendment to add a 'conscience clause' during the Republican National Convention's rules committee meeting. (C-SPAN)

Free the Delegates founder Kendal Unruh, the Colorado delegate and rules committee member who sponsored the conscience amendment, remained undaunted about the rejection of the conscience proposal, insisting, "it's not dead."

"I didn't have any unmet expectations," Unruh told CBC News hours after the vote in Cleveland, while walking back to her hotel from the convention centre at the Quicken Loans Arena. "There were some people who should have been with us that weren't, I had votes defect, they were being whipped really hard by the Trump people. I'm actually a little impressed they had that whip organization."

According to Unruh, 22 members of the 112-member rules committee voted to support the conscience amendment.

"And I just picked up a signer that did not vote with us on the floor," she added.

In an interview last week, Unruh called the effort "one last-ditch fight to defend the republic."

She holds onto hope that if Free the Delegates can pick up five more votes to achieve the required backing from a quarter of the group, or 28 members, it can still issue a "minority report" to the convention floor. That would compel the Cleveland delegates — all 2,472 of them — to engage in a limited debate on unbinding delegates before voting on the matter. A simple majority in favour of the rule change on the floor could bring it into effect.

USA-ELECTION/TRUMP

U.S. Republican presidential candidate Donald Trump speaks at a campaign rally in Bangor, Maine, on June 29, 2016. (Brian Snyder/Reuters)

Bring it on

Unruh technically has until Monday at 2 p.m. ET to accomplish that goal to force a minority report.

That being the case, Blackwell said there's a "conceivable" chance, however remote, that the "vote your conscience" insurgency could force a messy contested, multi-ballot convention.

Unruh says bring it on.

"If there's chaos, it didn't have to be this way."

As of now, Trump heads into Ohio with 1,542 delegates, surpassing the majority threshold he needs for a first-ballot nomination, according to an Associated Press tally.

Although Free the Delegates is keeping estimates of so-called conscience vote backers close to the vest, Unruh says it exceeds 400. Assuming most of them would spurn the real estate magnate, that would be sufficient to peel away Trump's majority.

It's a long shot, however. And it was made even trickier by a separate vote on Thursday that overwhelmingly reaffirmed Republican convention votes should bind delegates to the candidate their district voted for. Just 12 members of the rules committee were in favour of unbinding.

A doomed effort

There's a perfectly reasonable argument for preventing delegates from becoming free-agent voters, says Jim Bopp, conservative attorney and constitutional scholar.

"The problem is fundamentally that delegates are elected to represent the voters that sent them here to the conventions," he says.

Those voters establish certain conditions — one of which is that delegates vote on the first ballot for the candidate who the state wants. "Not who you want," Bopp added.

For her part, Unruh promised to fight on.

"I tried the decorum of the process, and now the RNC and Trump chose to have a floor fight. I still have until Monday to collect signatures for a minority [report]," she said. "This game just got very interesting."

Interesting is one way to put it. Trump campaign chairman Paul Manafort characterized it as more of a doomed effort that's just delaying the inevitable.

"Anti-Trump people get crushed at rules committee," he tweeted after the devastating vote. "It was never in doubt: Convention will honor will of people & nominate @realdonaldtrump."