Will they unite behind their party's standard-bearer? Will they sit out the 2016 campaign? Or will they fight on, in a quixotic quest to undermine Trump?
Trump's opponents are still sorting through the wreckage of the GOP primary season for a path forward. But it has become painfully clear over the past five days that party unification will be tough to come by, if it happens at all.
Past presidents, party leaders and prominent Republicans are all choosing sides, from unenthusiastic acceptance (Bob Dole) to pledges not to vote for either party in November (former Florida Gov. Jeb Bush
and Sen. Lindsey Graham
) to musings about a third-party bid (Bill Kristol).
Trump himself enters his first full week as the presumptive nominee by signaling that he has limited patience for or interest in the establishment's rebellion. Though the election is six months away, he announced Monday that New Jersey Gov. Chris Christie will lead his transition team.
And Trump will meet Thursday with Paul Ryan, after the House speaker's extraordinary announcement
to CNN's Jake Tapper that he's "just not ready" to support Trump.
But when CNN's Chris Cuomo gave Trump a chance to take on Ryan and the GOP establishment during a "New Day" interview Monday, Trump demurred. His response: "We'll see what happens."
He used the interview to offer fresh evidence of his willingness to thwart tradition. Trump, who is building his presidential bid around his business acumen and knowledge of the economy, told Cuomo the U.S. should take the unprecedented step of defaulting on the debt "because you print the money."
Trump's provocative style
Trump is making quite clear he doesn't intend to cast off the provocative style on the campaign trail that alarmed the Republican establishment and resonated so deeply with primary voters. After spending days on the receiving end of criticism from the likes of Ryan, Romney and Graham, Trump and his supporters hit back -- hard.
Sarah Palin, a key Trump surrogate and 2008 vice presidential nominee, took the unusual step of backing the little-known Republican businessman challenging Ryan for his Wisconsin seat.
"Paul Ryan is soon to be Cantored," Palin told Tapper Sunday on "State of the Union,"
referring to Eric Cantor, the former Republican House majority leader who was shockingly ousted by a primary challenger in 2014.
"His political career is over but for a miracle because he has so disrespected the will of the people, and as the leader of the GOP, the convention, certainly he is to remain neutral," Palin said. "And for him to already come out and say who he will not support is not a wise decision of his."
For his part, Trump didn't seem too worried about the talk of the GOP disintegrating because of his nomination. Speaking on ABC's "This Week," Trump questioned the need for party unity, arguing that his campaign is unlike any before and won't rely on the same political calculations.
"Does it have to be unified?" he asked. "I'm very different than everybody else, perhaps that's ever run for office. I actually don't think so."
He went on: "I think it would be better if it were unified. I think ... there would be something good about it. But I don't think it actually has to be unified in the traditional sense."
Those comments underscore the growing debate over whether Trump's unorthodox candidacy will doom the GOP in the fall or whether the anxious party leadership has grown so out of touch with the electorate that it's missing the genuine anger fueling Trump's rise.
"You have to draw the conclusion that there is some distance, if not a disconnect, between party leaders and members of Congress and the many voters who have selected Donald Trump to be the nominee of the party," John McCain
, the GOP's 2008 nominee, told CNN's Manu Raju Sunday on "State of the Union
. "You have to listen to the people that have chosen the nominee of our Republican Party."
Trump, meanwhile, is shifting his gaze to the general election by trying to undercut
Clinton's advantage with women.
Facing the likelihood of running against the first female nominee of a major party, Trump sought to recast Clinton's image by reviving the impeachment saga of the 1990s and arguing that she was dismissive of women who had extramarital affairs with her husband.
"Hillary was an enabler and she treated these women horribly," Trump said
Saturday in Spokane, Washington.
"And some of those women were destroyed, not by (Bill Clinton), but by the way Hillary Clinton treated them after it went down."
Trump is taking a risk with such comments
, and even Palin seemed to question their effectiveness.
When asked by Tapper about Trump's critique of Clinton, Palin said
, "a lot of people may be obsessed with a public figure's personal life, and they're going to get all entangled in, you know, past indiscretions or whatever."
"But I think, for the most part," she went on, "Americans are concerned about things like who will be able to appoint the next Supreme Court justices, which will affect an entire generation coming up. I think that's what people are concerned about, much more so than Bill Clinton's obvious indiscretions, and Donald Trump having been divorced a couple of times, but owning up to it."
Trump also caused some confusion over the weekend by taking positions on the minimum wage and taxes that are not only out of step with GOP tradition but also his own stances during the primary.
On taxes, he said levies on the wealthy would go up under his administration. He argued that while he supports across-the-board tax cuts, he would likely bargain away cuts for top earners during negotiations with Congress.
"On my plan, they're doing down," he said on "This Week." "But by the time it's negotiated, they'll go up."
He added: "We're going to submit the optimum ... That's what I'd like to get and we'll fight for it. But from a practical standpoint, it's going to get renegotiated. And in my opinion, the taxes for the rich will go up somewhat."
Raising the minimum wage?
And after he told CNN's Wolf Blitzer last week that he was "looking at" raising the minimum wage, he told ABC's George Stephanopoulous that he hasn't "decided in terms of numbers."
"But I think people have to get more," he said, while acknowledging the shift.
"I'm allowed to change," he said. "You need flexibility, George, whether it's a tax plan where you're going to -- where you know you're going to negotiate. But we're going to come up with something."
Such shifts, however, are deeply unnerving to many of Trump's opponents.
They have argued that he effectively fooled many primary voters into supporting him and will change his tune once he has to appeal to a broader electorate ahead of the general election.
That fear is partly what's fueling speculation over a potential third-party run from someone like Romney, who met privately with Kristol, the editor of the conservative Weekly Standard, last week to discuss how to get an independent candidate into the race.
Romney has been publicly mum about the prospect. But he clearly telegraphed his concerns about Trump in a commencement speech
Saturday at Trine University in Angola, Indiana, in which he warned of "demagogues."
"Profiteers tempt and endeavor to hook us with compulsive addictions," Romney said. "Entertainment media distracts us from the things that bring enduring achievements and happiness."