WASHINGTON – House Democrats are forcing Republicans to take a stand on President Trump's new position that the courts should completely overturn Obamacare.

Democrats are bringing up for debate Tuesday a resolution condemning the pending case as an "unacceptable assault on the health care of the American people."

It's Democrats' latest effort to take advantage of Trump's unexpected move last week to fully back a legal challenge to the 2010 Affordable Care Act without a ready substitute.

The decision surprised congressional Republicans who were focused on narrower health care measures – such as reducing the cost of prescription drugs – after failing in 2017 to come up with a replacement for the ACA.

White House acting chief of staff Mick Mulvaney said on CNN's "State of the Union" on Sunday that a one- or two-page proposal would be sent to Congress, and lawmakers could hash out the specifics.

But Trump tweeted late Monday that Congress wouldn't vote on the GOP plan until after the 2020 election.

Trump:President says Republicans' health care plan will go to vote after 2020 election

Senate Minority Leader Charles Schumer, D-N.Y., said Trump wants to "hold Americans hostage through the 2020 election when it comes to health care."

"He promises, 'Re-elect me and maybe you can take a peek at my backup plan after that' – which they don’t have," Schumer said at a news conference early Tuesday on the steps of the Supreme Court.

Democrats' resolution lists popular parts of the ACA that would end if the law is scrapped, including: protections for people with pre-existing health conditions; an expanded Medicare drug benefit; limits on how much insurers can charge older customers; subsidies for people who buy insurance on their own; expanded Medicaid eligibility for participating states; and allowing young adults to remain on their parents' insurance plans.

“It’s about so many things that perhaps they don’t understand," said House Speaker Nancy Pelosi, D-Calif. “The American people deserve to know exactly where their representatives stand on the Trump administration’s vicious campaign to take away their health care.”

Only three House Republicans sided with Democrats in January when, as one of Democrats' first acts after taking control of the House following a midterm election campaign focused on health care, they adopted a resolution to defend the ACA in the pending challenge.

Two of the three who crossed party lines – Reps. John Katko of New York and Brian Fitzpatrick of Pennsylvania – are among the 33 House Republicans that Democrats are targeting for defeat in 2020. Both also opposed House Republicans' Obamacare alternative in 2017.

More:White House chief of staff Mick Mulvaney guarantees no one will lose coverage if Obamacare struck down

New York Rep. Tom Reed voted for the replacement bill in 2017 but voted with Democrats in January to defend the ACA in court.

In December, a U.S. District Court judge in Texas sided with a group of Republican attorneys general who argue that the entire ACA became invalid after congressional Republicans eliminated the law's tax penalty for not having insurance coverage.

The law remains intact, pending a decision by the U.S. Court of Appeals for the 5th Circuit in New Orleans. Oral arguments have not been scheduled.

The Justice Department initially told the court it would defend the constitutionality of some of the law.

Last week, the department changed its position and notified the federal appeals court that it wants the entire ACA thrown out.

Congressional Republicans, however, would prefer to focus attention on many Democrats' push for a single-payer health care system, such as "Medicare for All."

"That," House Minority Leader Kevin McCarthy, R-Calif., said Thursday, "is a concern that we continue to work on."