But Mr. Trump’s choices reflect an unusual conviction: He said he had a “mandate” from his supporters to run as a fiery populist outsider and to rely on his raucous rallies to build support through “word of mouth,” rather than to embrace a traditional, mellower and more inclusive approach that congressional Republicans will advocate in meetings with him on Thursday.
Mr. Trump’s strategy is replete with risks. Roughly 60 percent of Americans view him negatively, according to pollsters, who say more-of-the-same Trump is not likely to improve those numbers. While a majority of Republican primary voters said they were looking for a political outsider, Mr. Trump will face a majority of voters in November who prefer a candidate with political experience, according to primary exit polls and several national polls. Many Republicans think they will lose the presidency and seats in the House and Senate if he continues using language that offends women and some racial and religious groups.
Still, Mr. Trump’s message, tone and policy ideas have drawn followers who are more passionate than Republican nominees typically enjoy, and he has monopolized the political conversation and news coverage of the race. Some Republicans argue that he cannot afford to change his stripes too much, while strategists in both parties say he is shrewdly sticking with a style that drowns out attacks that could deepen his negative rating.
“His rally rants and Twitter brawls are meant to dominate the media coverage and public conversation so that Democratic challenges have less space to break through all of the noise,” said Guy Cecil, the chief strategist and co-chairman of Priorities USA, the “super PAC” supporting Mrs. Clinton. “He doesn’t want people talking about his record or positions.”
Mr. Trump, in a telephone interview, compared his candidacy to hit Broadway shows and championship baseball teams, saying that success begot success and that he would be foolish to change his behavior now.
“You win the pennant and now you’re in the World Series — you gonna change?” Mr. Trump said. “People like the way I’m doing.”
He argued that he stood a better chance of inspiring voters in states like Ohio and Pennsylvania if he was his authentic self, rather than shifting from populist outsider to political insider to please a relative handful of Republican elites who are part of the establishment he has railed against for months. He said his huge rallies, where outbursts of violence and racist taunts have vexed many Republican leaders, and his attacks against adversaries on Twitter and in television interviews would continue because he believes Americans admire his aggressive, take-charge style.
“I think I have a mandate from the people,” Mr. Trump continued, referring to his victories in 29 states, including Nebraska and West Virginia on Tuesday night. “The people are tired of incompetent leadership at the highest level. They’re tired of trade deals that are ripping our jobs apart and taking their wages.”
Mandates are usually claimed after a presidential candidate wins a general election, not a party nomination, but part of Mr. Trump’s style and strategy is to project a supreme confidence in himself and his popularity with voters. Several Republicans said they put little stock in his claim, arguing that he had won support from only a fraction of the electorate and that he had yet to prove he was worthy of leading the entire Republican Party, rather than just his fractious and highly visible wing.
“Donald Trump did earn a mandate from Republican primary voters,” said Senator Patrick J. Toomey, a Republican facing a tough re-election fight in Pennsylvania, whose primary Mr. Trump won with 57 percent of the vote. “My advice to him is that he should now consider how he will appeal to the many Republican and non-Republican voters who have serious concerns about his candidacy.”
Former Senator Judd Gregg of New Hampshire said that electoral mandates were a fallacy in American politics, and that leaders only did well when they focused on “ideas in the center that unite people.”
“I don’t even think the 1980 Reagan landslide gave Reagan a mandate,” said Mr. Gregg, whose state gave Mr. Trump his first win in the primaries, and who has not decided if he will follow through on his pledge to support the Republican nominee. “He was effective because the country was in terrible shape and he was able to bring large numbers of people behind his ideas. Trump hasn’t done that.”
But Patrick J. Buchanan, the conservative commentator and past presidential candidate, said Mr. Trump was rallying historic numbers of voters with a mix of conservative ideas and anti-establishment populism that evoked, among other politicians, Ross Perot and his magnetic appeal in the 1992 campaign. Mr. Perot lost, of course, but Mr. Buchanan said that Mr. Trump might stand a better chance.
“With the largest Republican turnout ever, Trump eliminated 16 rivals and is on track to winning more votes than any Republican nominee in history,” Mr. Buchanan said. “That gives him a mandate to lead the Republican Party and move ahead with his plans to secure the border, pull back from foreign interventions and wars, and end these terrible trade deals.”
With many Republican leaders and elected officials torn between supporting their presumptive nominee and withholding their endorsement as leverage, Mr. Trump sounded torn himself. He said he wanted party unity but was unwilling to abandon the brand of politics and communication that has energized many Americans and divided others. He described his eight million followers on Twitter as a singular “advantage” and indicated that their support mattered more to him than the backing of Mr. Ryan, whose statement last week that he was “not ready” to endorse Mr. Trump led to the meetings Mr. Ryan is organizing on Thursday.
David Winston, a Republican pollster who worked on Newt Gingrich’s presidential campaign in 2012, said Mr. Trump was putting himself at a severe disadvantage in the general election.
“At this point, at a minimum, he’s at least 50 million voters short of what he’s going to need,” Mr. Winston said. “He has created an interesting dynamic in that, during the course of the campaign, he was basically calling those individuals names, which didn’t endear him to their supporters.”
Uniting people behind Mr. Trump is “eminently doable, but it will take significant focus,” he said.
In Mr. Trump’s view, the rallies and the Twitter wars — even when he is punching down against a little-known evangelical leader (Russell Moore of the Southern Baptist Convention) and a cable talk show host (Joe Scarborough of MSNBC), as he did recently — are crowd-pleasers, creating buzz that is critical to dominating the political landscape and overshadowing Mrs. Clinton’s message and attacks. Last week, he kept his commitments for rallies in Nebraska, Oregon and Washington State, even though he already had a lock on the nomination.
“In a Broadway theater, the best, the best, absolute best sale is called ‘word of mouth,’ ” said Mr. Trump, who once dabbled in theater producing. “If people love a Broadway show, it’s better than if you write a good review. Word of mouth is the No. 1 thing. And the word of mouth at my rallies is like, ‘You’ve got to go see it.’ And, you know, one person goes and they talk about it to 20 people.”
Over the coming weeks, Mr. Trump will offer policy speeches, including one on law and order, and another on judges — the latter being, in part, a response to conservatives who have said he cannot be trusted to pick Supreme Court justices.
But Mr. Trump is reluctant to trade in pitchfork populism for something more demure. He was gleeful, in fact, that so much attention was being paid to his Capitol Hill meetings on Thursday.
“Somebody said the paparazzi is going crazy over that meeting,” he said.
Author: PATRICK HEALY and MAGGIE HABERMAN