The rejection of the "unbinding" proposal was so overwhelming that committee leaders opted not to record the tally. Trump supporters on the committee quickly exercised procedural tactics to effectively kill any attempt to revive the issue -- and to codify that delegates are indeed bound to vote for the results of state caucuses and primaries.
Paul Manafort, the chairman of the Trump campaign, heralded the win, tweeting that an insurrection was "crushed."
Over the past seven months, as Trump easily won contests across the country, Republicans upset by his candidacy called for his ouster or for party officials to tweak the rules in order to keep him from winning the nomination. But only convention delegates -- not vanquished opponents or party pundits or top party donors -- had the power to change the party's rules and find a way to stop Trump, or at least make him sweat through the formal nomination process.
By June, like-minded anti-Trump delegates had found each other through social media and formed campaigns to explore how they could use the party's rules to snatch the nomination from Trump. Groups called Save Our Party, Free the Delegates and Delegates Unbound claimed the support of thousands nationwide and hundreds of convention delegates, but they failed to find enough support on the 112-member panel that sets the rules -- a body largely controlled by Republican National Committee Chairman Reince Priebus.
Although Priebus has clashed with Trump and his campaign operation, he has insisted for months that Trump is the party's nominee-to-be and that the party would not ignore the will of tens of millions of primary voters.
The profound rejection of the "unbinding" movement came just days before Trump is set to become the Republican presidential nominee and the night before he was poised to formally introduce his running mate, who is believed to be Indiana Gov. Mike Pence.
Throughout the day, the rules meeting was wracked by bitter feelings and protracted negotiations with delegates seeking to dramatically revamp the party rules. An impasse between Priebus and the group of delegates led to hours of cumbersome debate over proposed changes to the makeup of the party's governing structure, which ultimately failed.
Complicating the process, the committee was forced to take long recesses caused by a printer jam on the device responsible for printing proposed amendments. Later, the group recessed again to allow negotiations between party leaders and delegates on the differing proposals.
On one side of the talks was Ken Cuccinelli, the former Virginia attorney general, who is not a member of the rules committee but commands the votes of several members. He was seeking to return the party to closed contests -- meaning that only Republicans could vote in presidential caucuses and primaries -- and to make other changes to party operations.
Priebus and several members of the party's leadership support closed contests and agree in principle that awarding more delegates to states that hold closed contests is the best way to compel states to do so.
During talks that began Wednesday and stretched into Thursday morning, Cuccinelli said he proposed giving 20 percent more delegates to states that opted to hold a closed contest. Priebus and his team considered the offer but ultimately declined, according to multiple people familiar with the talks.
The impasse sparked hours of open debate by committee members on proposals that ultimately failed.
The committee rejected a proposed ban on lobbyists serving on the Republican National Committee. They also declined to repeal Rule 12, which allows the party to make changes to its nomination process in between national conventions. Priebus invoked the rule in early 2015 to change how the party hosts presidential debates and selects partner broadcasters amid concerns that GOP presidential candidates participated in too many televised debates during the 2012 cycle.
But the committee voted to establish a study committee to review the presidential nomination process. The new group will convene next year and is likely to once again explore overhauling the caucus and primary calendar by snatching away “first in the nation” status from New Hampshire, Iowa and South Carolina.
The panel also agreed to revert to old nomination rules that won't take effect until the 2020 presidential campaign. A candidate will need to win the plurality of voters in just five states in order to be placed into nomination -- instead of the eight that were required this year. The rules were changed in 2012 by supporters of former Massachusetts governor Mitt Romney's presidential campaign in order to stop a challenge by supporters of Rep. Ron Paul (R-Tex.).
Hovering at a far distance over Thursday's talks was Trump and his campaign. Manafort was spotted briefly at the rules committee meeting on Thursday morning but left soon after, telling reporters that the campaign was "not involved" in negotiations with anti-Trump delegates. During the day, word that Trump was likely to select Pence as his running mate didn't appear to stir the committee.
On the panel, special attention was focused on Sen. Mike Lee (R-Utah) and his wife, Sharon Lee -- two key swing votes in the debate over whether to unbind delegates. The couple joined Cuccinelli and other delegates in the closed-door negotiation, and the senator later spoke in favor of repealing Rule 12.
The Lees also voted for the plan to unbind delegates. But when it was introduced for consideration, the committee quickly killed it.
Kendal Unruh, a delegate from Colorado who led attempts to unbind delegates, was caught off-guard when called on to discuss her amendment and appeared to have misplaced papers she planned to use to help make her case.
"The right to conscience is not just something that we’ve decided is a cool idea, but we feel it’s the basis of our nation," she told the committee.
Allowing delegates to vote their conscience is "a God-given right," she added. "It’s why we have the Bill of Rights. It’s the reason you can’t force a doctor to perform abortions" if it violates their conscience.
Unruh and her allies insisted that they would have at least 28 votes on the committee to force a "minority report" allowing the group to introduce their idea to the full convention next week. It is unclear now whether they will be able to proceed with those plans.
Philip Rucker contributed to this report.