Michael Needham, chief executive for Heritage Action for America. (Nikki Kahn/The Washington Post)

Heritage Action for America, one of the leading conservative opponents of Republicans’ American Health Care Act, reiterated its opposition Monday despite days of arm-twisting by President Trump’s White House.

“Ryancare leaves the fundamental architecture of Obamacare in place,” Heritage Action chief executive Michael Needham said on an afternoon call with reporters. Needham was referring to the bill with the name of one of its biggest backers, House Speaker Paul D. Ryan. “We have one chance right now to pass a bill on a 51-vote Republican threshold. We can either use that to repeal Obamacare or not.”

Needham was among the conservative leaders invited to meet with Trump at the White House last week, a sit-down that the president’s social-media team promoted as a step toward calming the AHCA’s opposition.

But none of the groups present at the meeting — including Americans for Prosperity, FreedomWorks, the Tea Party Patriots and the Club for Growth — have backed off their campaign to stop the bill and demand a full repeal of the Affordable Care Act. FreedomWorks and Americans for Prosperity have been activating their grass-roots membership to lobby individual members of Congress; Heritage Action, Needham said, was ringing alarms for its 19,000 “Sentinels.” The push for a speedy replace-and-repeal plan, he said, reminded him of the push for Medicare Part D, which Republicans narrowly passed while holding the vote open for hours to lobby members.

“Sometimes doing the right thing takes courage,” Needham said. “The leader of the conservative opposition to that bill was Mike Pence. I don’t think he’s spent a single day regretting that vote. . . . Any conservative member who stands strong will never regret it.”

Needham also raised the stakes for Republicans on the upcoming AHCA score to be provided by the Congressional Budget Office. Some of the Republican criticism of the CBO, he said, was well taken. But Heritage Action is not going to be satisfied with a score that compares the AHCA with the ACA, Needham said. What would satisfy conservatives, he said, would be a CBO score comparing the new bill to the budget baseline before the passage of the ACA, a difference of billions of dollars.

Asked whether sinking the bill could force Ryan and Trump to pass a bill that Heritage liked even less, Needham said that the threat was a bad bill — period — that discredited conservatives.

“The biggest fear I have — what keeps me up at night — is that Republicans pass a health-care bill that keeps the fundamental architecture of Obamacare,” Needham said. “And then, in 2020 or 2024, the American people look at the mess and vote in a Democrat who says the answer is single-payer health care.”