WASHINGTON — Senator Dean Heller’s biting denunciation of the Republican health care bill last week infuriated the White House and helped unravel his party’s attempt to repeal the Affordable Care Act days before a vote was expected in the Senate.

Now Mr. Heller is facing an intense backlash in Nevada, his home state, where there is talk of a primary race challenge against him next year and a pair of the state’s wealthiest Republican donors are fuming.

America First Policies, a nonprofit group created to back President Trump’s agenda, suspended its advertising campaign against Mr. Heller after he agreed to attend a West Wing meeting on the health bill and after a group of Republican senators in attendance complained about the commercials. But Mr. Heller, perhaps the most vulnerable Republican senator on the ballot next year, has by no means escaped the wrath of Mr. Trump and his vocal supporters, including two billionaire casino magnates, Sheldon G. Adelson and Steve Wynn.

“All of the Trump supporters I talk to are furious with Heller,” said Danny Tarkanian, the son of the legendary Nevada basketball coach Jerry Tarkanian and a frequent Republican candidate for office in the state. Mr. Tarkanian said he was considering taking on the senator next year and had been encouraged to do so by some of the president’s ardent grass-roots admirers.

The political fallout from Mr. Heller’s high-profile news conference a week ago offers a vivid illustration of the new fault lines on the right in the Trump era. After years of fierce clashing between Republican hard-liners and mainstream conservatives, the purity-versus-pragmatist wars have given way to a new, Trump-centered debate that highlights how fully the president has taken over the party.

On the other hand, Mr. Heller faces enormous grass-roots pressure to stand his ground against the bill. He has clung tightly to his state’s popular Republican governor, Brian Sandoval, a staunch opponent of the repeal who accepted the Medicaid expansion dollars in the Affordable Care Act. More than 200,000 Nevadans have gained insurance through Medicaid since the passage of the health law.

What angered the Republican rank and file about Mr. Heller’s critique was not so much his unease with the compromise Senate legislation — a measure that many on the far right are also displeased with — but that he would so purposefully undermine the president’s agenda.

And it is not just party activists who are displeased with the senator.

Mr. Adelson and Mr. Wynn, two of Las Vegas’s leading gambling titans, each contacted Mr. Heller at the request of the White House last week to complain about his opposition to the Republican-written health overhaul, according to multiple Republican officials.

One ally of Mr. Heller’s acknowledged that Mr. Adelson and Mr. Wynn were unhappy with the senator at the moment and that their relationship needed some repair work.

Both billionaire donors are close to Mr. Trump, a fellow tycoon. Mr. Adelson played a pivotal role in Mr. Trump’s election, showering Republican groups last year with tens of millions of dollars. Mr. Wynn is the finance chairman of the Republican National Committee and oversaw a fund-raiser on Wednesday at the president’s Washington hotel that Mr. Trump said raised about $7 million for the party committee and his re-election campaign.

Earlier that day, America First Policies held a donor meeting for those who were in the capital for that evening’s fund-raiser. Every contributor who…