President Donald Trump could have Congress in an uncomfortable corner over the lawmakers’ exemption, and that of their staff, from Obamacare.

“I think he should just do it.”—@Heritage’s Robert Moffit

“This is one more instance of Congress passing an unpleasant, expensive, onerous law on citizens and then conferring a valuable benefit on itself,” Joe Morris, former general counsel for the Office of Personnel Management, told The Daily Signal.

Over the weekend, Trump tweeted that he could take away the exemption, granted by the Obama administration’s Office of Personnel Management, to prod Congress toward agreement on getting rid of Obamacare.

The provision provides what critics say is tantamount to an unconstitutional waiver for members of Congress and their staff from rules mandated by the Affordable Care Act, popularly known as Obamacare.

To exempt themselves, the 535 lawmakers and their more than 13,000 staffers are treated as if they were a small business employing fewer than 50 workers.

The exemption policy was created in an OPM directive under President Barack Obama, and could easily be overturned by Trump, said Morris, who worked at the agency during the Reagan administration.

Many critics of Obamacare, including a host of grassroots activists, long have argued that Congress and its staff should have to live under Obamacare like other Americans.

Morris said that applying Obamacare rules to Congress and its staff—as the language of the 2010 law actually requires—could prompt Republican lawmakers to act on their promise to repeal and replace the law. They failed to reach 50 votes to do so in the Senate last week, when three Republicans joined Democrats to scuttle a “skinny repeal” proposal that would have set up a conference with the House.

Such action by Trump, some political observers speculate, could spur Democrats to come to the bargaining table over the fate of Obamacare.

“Congress could feel the pain of most Americans,” Morris said. “It is worth trying. If members of Congress are aggrieved and their staffs are aggrieved, they might be more likely to take action.”

How the Exemption Works

Not a single Republican voted to pass Obamacare. Under a subsection of the Affordable Care Act, Democrats voted Congress out of its own employer-sponsored Federal Employees Health Benefits Program. The provision required members and House and Senate staff to enroll in the new health insurance exchanges created for other Americans under the law.

Obamacare subsidies are capped so that no one with income higher than $48,000 gets a subsidy. Members of Congress earn $174,00 annually.

On Aug. 7, 2013, the OPM—which administers the Federal Employee Health Benefits Program—determined that members of Congress and staff still could enroll in the program through the SHOP Exchange, a health insurance exchange set up to provide special insurance subsidies for small businesses in Washington, D.C., with fewer than 50 employees.

Morris co-authored a report for The Heritage Foundation, before the OPM finalized the change, that concluded the Obama administration had no statutory authority to make the rule.

In February 2015, then-Sen. David Vitter, R-La., a member of the Small Business and Entrepreneurship Committee, unsuccessfully sought documents pertaining to Congress and the exemption.

But documents that later surfaced reportedly showed administrators asserted Congress had a combined total of 45 employees. Congress itself has 535 members.

As of 2014, there were 4,180 Senate staffers and 9,175 House staffers, according to reports by the Congressional Research Service.

‘He Should Just Do It’

Though controversial, the move survived a legal challenge by Judicial Watch, a conservative government watchdog group that sued the District of Columbia’s small business insurance exchange on behalf of a city resident. Superior Court Judge Herbert B. Dixon Jr., however, determined the OPM’s action was legal.

Doing away with the exemption for lawmakers and their staffs certainly suits Trump’s campaign pledge to clean up Washington perks and privilege, said Robert Moffit, senior health policy analyst at The Heritage Foundation.

“If you are talking about draining the swamp, this would be a direct assault on the swamp creatures in eliminating what is clearly an illegal insurance subsidy,” Moffit told The Daily Signal, adding:

I don’t think the president should use this as a threat to get Congress to repeal. I think he should just do it. The funds are not drawn from any statutory authority. Trump could have Congress in a very, very difficult spot.