WASHINGTON — President Obama took his motorcade to Capitol Hill Monday to huddle with congressional Democrats about how to protect his signature legislative achievement from being dismantled.

The extraordinary meeting came as the incoming vice president, Mike Pence, held a similar strategy session with with Republicans across the Capitol. With President-elect Donald Trump's inauguration now just 16 days away, Republicans are laying the procedural groundwork to dismantle the the law known as Obamacare — the 2010 health insurance law that Obama has been able to protect only through his veto pen.

So with demise of Obamacare apparently a foregone conclusion, the question for both camps is what to replace it with

Obama's message: Democrats should fight to expand health coverage for uninsured Americans — and to work with Republicans if they have ideas to do that.

"The president has long been open to the idea that if there are Republicans who are genuinely interested in reforming the Affordable Care Act in a way that would strengthen the program, the president would be strongly supportive of that effort," White House press secretary Josh Earnest said. "But that's not what Republicans have."

It was Obama's first trip to Capitol Hill since his final State of the Union Address a year ago — and likely his last as president before he escorts President-elect Donald Trump to the Capitol for his inauguration on Jan. 20. He walked into the closed-door meeting in the Capitol Visitors Center auditorium flanked by Senate Minority Leader Chuck Schumer, D-N.Y. and House Minority Leader Nancy Pelosi, D-Calif.

Tweeting from the sidelines, President-elect Trump suggested that Republicans should show no mercy.

"Republicans must be careful in that the Dems own the failed Obamacare disaster, with its poor coverage and massive premium increases," Trump tweeted. "Also, deductibles are so high that it is practically useless. Don't let the Schumer clowns out of this web."

On Tuesday, the first day of the new 115th Congress, Senate Budget Committee Chairman Mike Enzi, R-Wyo., introduced a budget resolution that would pave the way for the repeal of the Affordable Care Act. A vote on Enzi's bill could come as early as next week.

Also on Tuesday, the House passed a rules package that makes it easier for Republicans in that chamber to scrap Obamacare.

Republican leaders are using a procedural tactic called budget reconciliation, which requires only a simple majority of lawmakers to repeal the law. The process requires only 51 votes in the Senate and 218 in the House. Republicans hold 52 seats in the Senate and 241 in the House.

The tactic prevents the possibility of a filibuster, but can be used only once a year. So if Republicans repeal the law without a replacement, it could be months or years before Congress is able to agree on a replacement health care law.