WASHINGTON — As his party splinters and his policy agenda faces peril, House Speaker Paul D. Ryan will enter his meeting with Donald J. Trump on Thursday increasingly at odds with a growing, if grudging, Republican congressional majority willing to embrace Trump as their candidate.
The decision of Ryan, the party's most prominent skeptic of its polarizing new standard-bearer, will echo well beyond this campaign season when he anticipates rebuilding his party's post-Trump brand, possibly with the speaker himself at the top of the 2020 presidential ticket.
"To pretend we're unified as a party'' would lead Republicans to "go into the fall at half sprint," Ryan said Wednesday after meeting with GOP House members. He suggested that he hoped Trump would show an openness to change on both substance and tone when they meet on Thursday.
But Trump has said he has no intention of reinventing himself for the general election — a declaration that could force Ryan to acquiesce in the name of Republican unity or establish himself as the leading voice of opposition within the party.
While Ryan has repeatedly cited his desire to unify his party and to reject the nasty tone of the Republican primary campaign, he appears to have complex motivations.
He and his staff play down talk of a 2020 run for the White House, but how Ryan manages Trump over the next six months will play a major role in shaping Ryan's future. Many of his colleagues are uneasy about Trump and grateful that the speaker is at least buying them time to determine how to handle the political equivalent of a live grenade.
Many congressional Republicans also view Ryan as a tantalizing prospect for the White House.
"I think he'd make a great president," said Sen. Roy Blunt, R-Mo., echoing a view shared by others like Ryan's predecessor, former Speaker John A. Boehner, and Sen. Orrin G. Hatch of Utah.
Still, there are Republicans who have little use for Ryan's reluctance to support Trump and say the time for hand-wringing has passed.
"He's going to be the nominee," said Sen. Richard M. Burr, R-N.C. "So the choice is him or a Democrat. And that makes it a little tough to figure out why people are saying 'I've got to wait to hear more.'"
Ryan's immediate goals, his advisers say, are to advance his agenda and protect the Republican majority in the House. Many of those goals involve policy that is sharply different from Trump's brand of hard-edged nationalism.
Ryan's desire to overhaul the immigration system, rein in the nation's entitlement programs, promote vigorous free trade and push other aspects of traditional conservatism have been as welcome to Republican voters this year as carpenter ants at a home inspection.
This has alarmed the speaker because it bodes poorly for his chances for advancing what he calls "reform conservatism."
Those close to Ryan say he tends to put his policy agenda before party loyalty.
"People in politics tend to be in two categories," said Peter Wehner, a director of the White House Office of Strategic Initiatives under President George W. Bush, who has known Ryan for two decades.
"Some are drawn to politics because they like the games and mechanics, and their first priority is the party," Wehner said. "Bob Dole fell into that category. Mitch McConnell is also that party guy. And Ryan is just more in that camp of ideas, and he thinks about the party mostly as a vehicle to advance conservatism."
Ryan's associates say he has also been repulsed by Trump's bombastic tone and proposals like his call for a ban on Muslim immigration.
But he is just as motivated by his concern for protecting his House majority, something that was not even in question until Trump became the presumptive nominee. Although many analysts say the majority is safe for now, some of the most endangered House Republicans come from districts where Trump could be particularly damaging to their prospects.
There is, for example, little upside to Trump for Republicans like Rep. Robert Dold, who represents the moderate-leaning North Shore Chicago suburbs, or Rep. Carlos Curbelo, who has a heavily Hispanic district in South Florida.
No former House speaker since James K. Polk has gone on to win the presidency, but if Ryan started a campaign in four or eight years he would begin with a formidable network of donors built up during his time in the House and while he was Mitt Romney's running mate in 2012.
Romney may be the biggest booster of a future Ryan White House campaign.
"I would love to see him run for president," Romney said of Ryan at a private fundraiser in Washington last week for an Israeli university. A recording of Romney's remarks was shared with The New York Times by an attendee.
Ryan has deepened his connection to the Republican donor universe since taking over the speakership last year, raising $23.5 million for his House colleagues.
Dan Senor, a friend of Ryan's who advised him during the 2012 White House race, said he was skeptical that the speaker would try to use the House as a presidential launch pad.
"The building of the machine would be easy, it's just a question of if he actually ever wants to do it," Senor said. "I don't think he will."
While Ryan is seen as an institutional Republican relative to Trump, he draws from a brain trust that exists in large part off Capitol Hill.
A protégé of Jack Kemp, the former Republican congressman from New York, Ryan is a "free markets and free people" conservative of the sort venerated by The Wall Street Journal editorial page.
His outside informal consulting group includes Wehner; George Weigel, a founding president of the conservative James Madison Foundation; Yuval Levin, a founding editor of National Affairs; and many from Kemp's world. "Paul is very interested in Catholic social doctrine, which is something I have written about extensively, so we talk a lot about that," Weigel said.
But this year, at least, Republican primary voters demonstrated no appetite for Ryan's style of aspirational conservatism, having rejected both Sen. Marco Rubio and former Gov. Jeb Bush, both of Florida.
Still, what ultimately may push Ryan toward a presidential run of his own is rooted in the agonizing situation he is enduring right now: a recognition that his ambitions for remaking his party into something that reflects his vision will not be realized outside of the White House because his push for an overhaul of the nation's tax, entitlement and poverty programs toward a more free market orientation may be stymied unless he becomes president.
"He has now seen the power of the bully pulpit," said Bob Wood, a lobbyist and, like Ryan, native Wisconsinite.
While Ryan keeps his eyes on getting through 2016, many of his Republican colleagues are clearly looking to 2020. Sen. Ben Sasse of Nebraska, a Never Trump leader, is widely viewed as angling for a run, as is Sen. Tom Cotton of Arkansas; Cotton's state is considering a bill that would make it easier for him to run for re-election and the White House at the same time.
But most eyes are currently on Ryan, his demurrals notwithstanding.
"He says he's not," Burr said. " I take everybody at their word." Then he paused. "Some mornings, I feel like I'm the only one looking in the mirror that doesn't see the next president up here."