Many party leaders and rising stars have steered clear of Cleveland. Ohio Governor John Kasich, a vanquished Trump rival, had no plans to attend the convention.
Top Trump adviser Paul Manafort said "John Kasich is being petulant. He's embarrassing his party, he's embarrassing his party in Ohio."
Monday's opening night speeches included an odd mix of politicians - Senator Joni Ernst of Iowa and Senator Jeff Sessions of Alabama - as well as immigration advocates, a marine who fought in the Benghazi attack and entertainers, including actor Scott Baio and Willie Robertson, star of Duck Dynasty.
The theme was "Make America Safe Again" from a self-described law and order candidate. Delegates are due to vote on Monday afternoon on the rules that will govern the convention week, and insurgent delegates circulated a petition trying to force a state-by-state vote - a move that could disrupt floor proceedings even if they fail. On Sunday, 14 insurgent members of the convention rules committee emailed their fellow GOP delegates asking them to oppose the rules that panel approved, saying its proposals included "abuses of power", ABC news reported. Trump's opponents want to change a rule that requires delegates to vote for the candidate to whom they were committed after state primaries and caucuses. Trump's nomination is essentially automatic under the current rules, because he has far more than the 1,237 delegates required to win. Some rebellious delegates threatened to walk out if they were thwarted. Should that occur in significant numbers, it could leave television cameras panning across empty seats.
"We won't sit around and coronate a king," said Colorado delegate Kendal Unruh, who like many rebels has backed vanquished presidential contender Senator Ted Cruz of Texas. Trump's campaign dismissed the effort. "It's not a movement," Manafort said on Monday morning at a Bloomberg breakfast. "It's some rogue, recalcitrant delegates." The roll call vote on the nomination was expected on Tuesday, with Trump scheduled to close the convention with an acceptance speech on Thursday.
Trump would gain the nomination at a time of crisis and tumult at home and abroad, punctuated by the deadly shooting of three police officers in Baton Rouge, Louisiana. The convention comes as a former Marine ambushed police in Baton Rouge, shooting and killing three law enforcement officers less than two weeks after a black man was fatally shot by police there in a confrontation that sparked nightly protests that reverberated nationwide. Three other officers were wounded Sunday, one critically. Police said the gunman was killed at the scene. President Barack Obama, responding to the shooting on Sunday, noted that the incidents had come just before political conventions that tend to involve "overheated" rhetoric. But Trump, insinuating that Obama held some responsibility, earlier blamed a "lack of leadership" for the Baton Rouge shootings and added on Twitter, "We demand law and order."