DENVER (AP) — Should he win the Republican nomination, Donald Trump’s most plausible path to victory in the general election would be a GOP map unlike any in years. He’d be relying on working class, largely white voters in states that have long been Democratic bastions in presidential contests, from Maine to Pennsylvania to Michigan.

To make that work he’d have to thread a narrow needle — not only holding on to those core supporters but also softening rhetoric that has alienated black and Latino voters and calming those in the GOP who vow to never vote for him.

It could be tricky, but the past eight months have taught political professionals in both parties not to underestimate the man.

Republican presidential candidate Donald Trump waves during a campaign stop Friday, Feb. 19, 2016, in North Charleston, S.C. (AP Photo/Matt Rourke)

Republican presidential candidate Donald Trump waves during a campaign stop Friday, Feb. 19, 2016, in North Charleston, S.C. (AP Photo/Matt Rourke)

“He attracts a different kind of voter,” said GOP pollster Frank Luntz. “It’s a completely different equation.”

Trump has signaled he’s already thinking about the general election, bragging that “we’ve actually expanded the Republican Party” and slamming Hillary Clinton as part of the political establishment that’s to blame for the sour economy.

“She’s been there for so long,” Trump said after notching seven victories on Super Tuesday in states as diverse as Massachusetts and Alabama. “I mean, if she hasn’t straightened it out by now, she’s not going to straighten it out in the next four years.”

Trump has dominated a majority of Republican primaries by combining his celebrity and can-do demeanor with a message that once was off-limits in both parties — a full-throated demand to restrict both trade and immigration. That’s now a potent mix for voters from any party who’ve seen jobs vanish and wages stagnate in an increasingly globalized economy.

“Immigration and trade policy changes the winners and losers, and the people who are going to be in play are the ones who are the losers in that process,” said Roy Beck of Numbers USA, which advocates limiting immigration. “This has the potential to turn out a lot of voters.”

Trump has boasted that he could win even Democratic strongholds like his home state of New York. Analysts say that’s unlikely, and he may face a tough climb in more diverse or well-educated states like Colorado, Florida and Virginia that have traditionally been presidential battlegrounds.

Instead, Trump may best appeal to the Rust Belt, from Pennsylvania through Wisconsin, an area that’s been a bedrock of Democratic presidential victories but is reeling from job losses and still struggling to recover from the recession.

“The path for Trump is through the Rust Belt,” said Simon Rosenberg of the New Democrat Network, a center-left group in Washington that studies the electorate. “It doesn’t mean it can’t get done, but he will have to do things that no one has ever done as a Republican.”

Trump will also have to contend with basic mathematical realities of an electorate that has been favoring Democrats as it’s become increasingly diverse.

Though Trump’s vowed he’ll win Latinos, it’s unlikely he’d outdo Mitt Romney’s performance with Hispanics in 2012, and he could probably count on only modest improvements among blacks. That might require him to win even more of the white vote to prevail in the election than the 63 percent Ronald Reagan captured in his 1984 re-election, when Reagan 49 states.

“He’s going to be battling on very different terrain if he’s the nominee,” said William Galston of the Brookings Institute.

Finally, Trump would have to bridge divides with Republicans who say they won’t vote for him because of what they see as his demagoguery, breaks from conservative thinking and his personal conduct. Romney, the party’s most recent presidential nominee, has blasted him as a “phony.”

“I can’t tell you how many suburban Republicans Trump will lose to us, but he’ll lose plenty,” predicted Ed Rendell, former Democratic governor of Pennsylvania, though he acknowledged that the billionaire developer also could pick up some union members who would otherwise vote Democratic. “My gut reaction is he’ll lose more suburban independents than gain Reagan Democrats.”

He added: “It scares you a little bit because you just don’t know.”

Trump supporters believe he’s being underestimated again. Ed McMullen, Trump’s South Carolina chairman, noted that the candidate had broad appeal in his state — winning women, college graduates and evangelicals.

“I think clearly what happened with Mr. Trump was the message was not something that was only hitting one group,” McMullen said. “It was not just angry white men.”

Celinda Lake, a Democratic pollster, said Democrats will have to use ads to blunt Trump’s apparent strength with economically disaffected voters.

“One of the challenges will be defining Trump around the economy,” Lake said. “This is a guy who could win or implode.”