The day began with news that Trump and House Speaker Paul Ryan -- who unleashed a political earthquake Thursday when he said he wasn't yet able to support the Republican presumptive nominee -- would meet
with Republican National Committee Chairman Reince Priebus and top Hill Republicans in an effort to unify the party. By Friday night, however, talk circulated that leading conservative commentator William Kristol had reached out to 2012 Republican nominee Mitt Romney to help enlist a strong third-party candidate in a last-ditch effort by anti-Trump conservatives to thwart the real estate magnate's bid.
Meanwhile, former Vice President Dick Cheney and 1996 Republican nominee Bob Dole said they were supporting Trump. South Carolina Sen. Lindsey Graham and former Florida Gov. Jeb Bush, however, said they planned not to vote in November.
President Barack Obama even waded into the debate.
"I just want to emphasize the degree of which we are in serious times, and this is a really serious job," Obama told reporters at the White House. "This is not entertainment. This is not a reality show. This is a contest for the presidency of the United States."
'This is what the people want'
Ryan left the door open Thursday when he said he hoped to eventually back Trump and "to be part of this unifying process." That olive branch seemed to arrive early Friday afternoon when he announced he would meet with Trump next week "to begin a discussion about the kind of Republican principles and ideas that can win the support of the American people this November."
But Trump, speaking to ABC News' George Stephanopoulos, said he doesn't need to earn Ryan's support, previewing a message
he'll deliver to the speaker next week.
"I'm gonna say, 'Look, this is what the people want,'" Trump said.
That echoed a rebuke Trump tweeted about Ryan earlier in the day: "Paul Ryan said that I inherited something very special, the Republican Party. Wrong, I didn't inherit it, I won it with millions of voters!"
Republicans pick sides
Endorsements -- and vows not to endorse -- tumbled in Friday. Graham, himself a 2016 contender, spoke at length to CNN's Dana Bash
about his distaste for Trump and said he would not vote for Trump or Hillary Clinton.
"I think Donald Trump is going to places where very few people have gone and I'm not going with him," Graham said, also citing Trump's "temperament" as unworthy of a potential president.
Trump responded to Graham's criticism in kind, sending out a missive mocking the senator for his failed presidential bid and saying his "military strategies have failed."
"I fully understand why Lindsey Graham cannot support me. If I got beaten as badly as I beat him, and all the other candidates he endorsed, I would not be able to give my support either," Trump said.
Bush similarly said Trump had "not demonstrated" the necessary "temperament or strength of character" for the Oval Office, breaking a pledge
he made in February to support the GOP nominee, even if it turned out to be Trump.
Trump dismissed Bush's criticism at a rally in Omaha, Nebraska, on Friday.
"I won't talk about Jeb Bush. I will not say, I will not say that he's 'low energy,'" Trump said, reviving a memorable moniker for his old foe.
As he dismissed Graham and Bush, Trump was heralding the support he picked up from Cheney and Dole, who expressed their desire to support the GOP nominee over Clinton.
"The voters of our country have turned out in record numbers to support Mr. Trump. It is important that their votes be honored and it is time that we support the party's presumptive nominee, Donald J. Trump," Dole said in a statement released by Trump's campaign. He added: "We must unite as a party to defeat Hillary Clinton."
At the same time, other Republicans offered their support for Trump -- some of it half-hearted and out of a mixture of loyalty to the Republican Party and a desire to keep Clinton from the presidency.
Rep. Peter King, who in February called Trump "unqualified to be president," said on CNN's "The Lead"
that he endorsed Trump, "but not with enthusiasm."
Idaho Rep. Raul Labrador, a former Ted Cruz supporter, said on CNN's "The Situation Room" that he would support Trump but not participate in his campaign until the presumptive nominee "grew up a little bit."
Romney discusses third-party candidate
As Republicans declared their allegiances, The New York Times reported that Trump had tasked his son-in-law, Jared Kushner, to work with his campaign and help set up a transition team
should he win the White House. But word also surfaced that Romney had met with leading conservative editor William Kristol to discuss
how best to get an independent candidate into the presidential race.
Kristol, the editor of The Weekly Standard, told CNN Special Correspondent Jamie Gangel that he's working to get a strong independent candidate and wanted Romney's thoughts on who it might be, how it could be done and whether Romney would help -- to which Romney agreed.
Kristol then suggested that Romney should consider whether he "might be the candidate" -- although Kristol qualified the remark by saying he's not "actively working to get him to run."
A message left with a spokeswoman for Romney was not immediately returned.
Trump hammers Clinton
But despite all the GOP infighting, Trump still found time to take shots at leading Democrats. He engaged in a heated Twitter fight
with Massachusetts Sen. Elizabeth Warren over her claim that she has Native American ancestry in a response to her allegations earlier in the week that Trump had built his campaign on racism and xenophobia. And speaking at an evening rally in Eugene, Oregon, Trump accused Clinton of being "an unbelievably nasty, mean enabler" of her husband's alleged affairs and accused her of destroying the lives of his accusers.
"She's been the total enabler. She would go after these women and destroy their lives," Trump said, accusing Clinton of "disgraceful" behavior.
A message left with the Clinton campaign Friday night was not immediately returned.
Trump predicted that the Clinton campaign would counter by using crude comments he has made about women and sex in interviews with talk radio host Howard Stern against him in attack ads.
In his defense, Trump said he made his controversial remarks before he knew he would seek the presidency.
"Don't forget," Trump said, "I was never going to run for office."