Republican-backed efforts to stop Donald Trump from claiming the party's presidential nomination have flopped over the last four months.

Mitt Romney's call for GOP voters to rise up against the real-estate mogul didn't work. Trump easily defeated his Republican rivals in the primaries of late April and early May, forcing Ted Cruz and John Kasich out of the race. Super PACs formed to run ads against Trump in the later stages of the primaries lacked cohesion and leadership and failed to attract enough big-money donors. And attempts to attract an independent candidate fizzled.



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Trump now heads into the Republican convention, which begins 10 days from now, with 1,541 delegates - well over the 1,237 needed for majority to win the GOP presidential nomination.



Still, there's a chance - no matter how small - that Republican delegates opposed to Trump could spark an uprising that might jeopardize his nomination. And here are three ways they could do it beginning as early as next week:



Unbinding the delegates



Anti-Trump rebels are trying to pass a rule at the Rules Committee meeting Thursday in Cleveland to "codify" the idea that delegates are able to vote their conscious - for whomever they want, even if they are currently bound to Trump on a first ballot.



If that proposal fails, as expected, Trump's opponents are hoping to win over 28 of the 112 Rules Committee members (25 percent) who will be meeting that Thursday to force the full convention to consider whether to unbind the delegates. It's called a "minority report."



Republican super-lawyer Ben Ginsberg explains that if anti-Trump forces can somehow muster the 28 votes to produce a minority report, the floor vote could be interesting, because there's a higher concentration of Trump loyalists on the Rules Committee than on the floor.



"I think there is a chance, but it's a remote one," Ginsberg said Thursday on MSNBC.



Kendal Unruh, the Colorado delegate who's leading the "Free the Delegates" movement, insists that she has enough for a minority report.



"We are in wait and see mode," she says.



Finally, if all efforts fail in the Rules Committee, anti-Trump delegates could cause disruption on the floor and attempt to force a vote of all delegates.



Requiring a supermajority to capture the nomination



There's a significant downside to any push to unbind the delegates: It essentially invalidates the five months of Republican primaries and caucuses used to choose the delegates. And many of these GOP leaders could find move unseemly and undemocratic.



So another way to stop Trump at the convention would be for the Rules Committee to vote to require a supermajority - instead of a simple majority - to win the GOP nomination.



Allowing delegates to abstain

A third way how anti-Trump delegates could dump Trump is by abstaining from their vote to keep Trump below the 1,237 number needed for a majority on the roll-call vote.

Ginsberg says that whether a delegate can abstain from his or her vote on a first ballot is likely to come down to a ruling by the chair.

The smart bet is that none of these scenarios is successful. Most Republican delegates, by nature, aren't rebels. They're go-along-get-along party leaders who probably aren't eager to overturn the will of the voters. More importantly, a real presidential alternative to Trump has yet to emerge. After all, it's hard to beat somebody with nobody.

But keep an eye on two developments over the next week -- 1) whether Trump continues to veer off message, ad 2) poll numbers in key Senate races. If these delegates are 100 percent convinced Trump would be a down-ballot disaster for Republicans, the chances of rebellion could increase.

Yet until then, prepare for coronation instead of an insurrection.