But the rise of Donald Trump and the Republican Party’s embrace of the real estate mogul have driven DeSouza away from the GOP.

The 33-year-old communications professional worked for the Treasury Department under George W. Bush. He believes in free trade, less government involvement in the economy, and a strong foreign policy.

WASHINGTON — On paper, Andrew DeSouza looks like the face of the Republican Party’s future.

“I would say at this point I am a man without a party,” said DeSouza, who plans to vote for Democratic presidential nominee Hillary Clinton this fall though he’s not joining the Democratic Party. “I hold certain values that I deem to be conservative, but the party where it is now, I don’t even know where it is. It’s some reactionary force to generational trends that are so against what I find to be important in terms of values and policy positions.”


Trump is losing millennials in droves, recent polls show, and some party leaders are deeply worried that trend has dangerous implications for the party’s future beyond the 2016 election.

Clinton has an almost three-to-one advantage over Trump among younger Americans in the latest polling. The former reality TV star could lose the youth vote by the largest margin in modern political history if the current trend persists.

For many millennials eligible to vote in their first presidential election, Trump is their introduction to the Republican Party and to presidential politics.

In interviews with the Globe, some right-leaning millennials said they were turned off by what they saw as his bullying style and divisive comments toward women, Muslims, and others. Some of his central policy positions, they said, such as building a wall between Mexico and the United States to keep out illegal immigrants, are disturbing or preposterous. They said they don’t think he has the character or temperament to be president.


“I don’t really take any of Donald Trump’s policies seriously,” said Miguel Undurraga, a member of the Harvard Republican Club, “What I take more seriously is the kind of person who makes those comments.”

The risk for the Republican Party is that Trump, and all that young voters don’t like about him, becomes inextricably linked with the image of the party in millennial minds.

“The country that Donald Trump talks about is not in any way in line with the experiences of young voters right now. They don’t see the world the way he sees it at all,’’ said Tim Miller, a top adviser to Jeb Bush’s primary campaign and outspoken Trump critic. “That disconnect is so stark that it is turning them viscerally away from him in particular and also the party, and that’s a problem.”

The Trump campaign did not respond to a request for comment.

Trump greeted the crowd Saturday as he arrived to speak at a rally in Fredericksburg, Va. Gerald Herbert/Associated Press

The millennial generation, loosely defined as Americans born between 1980 and 2000, is a key prize for both major parties. More than 69 million members of this generation are of voting age, making them a potential voting bloc almost as large as that of the baby boom generation, according to the Pew Research Center, although they have so far consistently turned out to vote in lower numbers than older voters.

Their views and votes will only matter more in the years ahead: In April, their total numbers surpassed those of the baby boomers to become the largest living generation.


And an awful lot of them seem to hate Donald Trump.

Clinton is thrashing Trump 56 percent to 20 percent among Americans under 35, according to a USA Today/Rock the Vote poll released last week.

Clinton has her own millennial concerns. Her Democratic primary rival, Bernie Sanders, crushed her among younger voters by a 78-to-21 average, according to exit poll data compiled by Tufts University’s Center for Information & Research on Civic Learning and Engagement.

Polls suggest that many of these young Sanders followers are inching their way toward embracing Clinton but not necessarily with the same enthusiasm.

For Republicans looking beyond the top of the ticket, and beyond 2016, the numbers in the USA Today poll are more troubling: Half of those surveyed said they identified with or leaned toward the Democratic Party, while just 20 percent identified with or leaned toward the GOP.

Veteran GOP strategist Barry Bennett rejected the notion that Trump was somehow hurting the Republican Party among younger voters. “The truth is, they turn out in abysmally small numbers,” he said of millennials, in keeping with young voters of previous generations.

When they get older, they will vote in higher numbers, but by then their attitudes will have changed drastically and they will be more conservative, he predicted.

Many millennials are angry at the government because they can’t find jobs and feel as though their slice of the American Dream is slipping away; that provides an opening to Trump to win over some of them if he focuses his message, Bennett said. “He can speak to that.”


But others in the party are very worried.

“His campaign paints the picture of all Republicans being misogynists and racists, and obviously that isn’t true, but when you’re young and you’re an undecided voter trying to align with a party, Donald Trump as the face of the Republican Party isn’t very beneficial,” said Sapna Rampersaud, 19, a member of the Harvard Republican Club, which publicly declared it was not supporting Trump earlier this month, the first time in its over 125-year history the group hasn’t backed the party’s standard-bearer.

Rampersaud says she will probably vote for one of the third-party candidates but is still a Republican.

Fellow club member Undurraga, on the other hand, changed his California voter registration to “no preference” the day after Trump effectively clinched the nomination so he could vote for Clinton in his state’s primary, and he plans to vote again for her this fall. The 20-year-old considered taking a job doing Latino outreach for the Clinton campaign in Ohio, but ultimately decided against it because he’d have to take off a semester of school. He said he will volunteer once he’s back on campus in the fall.

“She is more stable, she has the experience, and what’s most important for me, in an era where Washington is just so plagued by partisan gridlock, we need somebody with big tent policies and the ability to compromise,” said Undurraga.


Trump spoke to supporters Friday in Dimondale, Mich. Carlo Allegri/Reuters

Forces within the GOP are trying to help the party respond to its millennial problem. In June, the College Republican National Committee published a report, based on polling and focus groups with Americans aged 18 to 29, that concluded young voters don’t believe Republicans care about many of the issues that matter most to them. Their top issues included fixing troubled schools, promoting clean energy, reducing the national debt, and addressing poverty.

The report was part dire warning, part game plan for how to win over the millennial generation. That playbook included having Republican candidates show themselves as empathetic, pursuing policies that demonstrate the GOP cares about people from all walks of life — a value that emerged as paramount among the millennials surveyed.

The authors also said their research indicated millennials are attracted to market-based solutions to problems, a core Republican belief but one that the party needs to communicate better to younger voters. Candidates should cast their policy approach as modern and innovative, after the fashion of Uber, and cast the other side as “an old, yellow taxi-cab company,” the report said.

Though Trump was not mentioned by name, the implication about his candidacy was clear.

“In 2016, if we continue to confirm the cliché of the GOP as visionless, angry, and unkind, we risk bringing upon ourselves a [Walter] Mondale-like presidential defeat, and we might lose the US Senate, suffer a catastrophic loss of seats in the House, and threaten modern highs in state-level offices and state legislative majorities,” the report said.

For DeSouza, the former Bush administration official, his rupture with the GOP is not just about Trump.

He pointed to the platform Republicans adopted at their convention, which moved further right than the already-conservative document approved in 2012 and included several provisions expressing disapproval of homosexuality and same-sex marriage.

Among them is a section that DeSouza and other critics say supports so-called conversion therapy for gays and lesbians.

“It was just completely against where we are as a country,” said DeSouza, who is openly gay. “It’s a step back decades from where we are and what kind of country we are right now.”

He has also been disappointed to see party leaders such as House Speaker Paul Ryan embrace Trump.

“Where has the party leadership gone to say ‘This is not who we are’ to a generation?” he said. “Their silence is deafening.”

Victoria McGrane can be reached at victoria.mcgrane@globe.com. Follow her on Twitter @vgmac.