By Matt Hoffman, Buzz60

President Trump has thrown his weight behind House Republicans' new bill to repeal and replace Obamacare. But he knows the stakes for the party are high.

He held a closed-door meeting with House Republicans on Tuesday.

CNN reports that he warned of a "bloodbath" in the 2018 midterm elections if the party can't deliver on their anti-Obamacare promises.

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12 PHOTOS Sen. Rand Paul asks House GOP for Obamacare replacement bill See Gallery Sen. Rand Paul asks House GOP for Obamacare replacement bill Sen. Rand Paul demands a copy of the bill. This staffer says she can't give him one. https://t.co/gPo5rMsUkS I have been told that the House Obamacare bill is under lock & key, in a secure location, & not available for me or the public to view. I am heading to the secure location where they are keeping the House obamacare bill. I will demand a copy for the American people. @RandPaul This is unacceptable. This is the biggest issue before Congress and the American people right now. @RandPaul What is the House leadership trying to hide? My guess is, they are trying to hide their "Obamacare Lite" approach. @RandPaul Renaming and keeping parts of Obamacare, new entitlements and extending medicaid expansion are not the #FullRepeal we promised @RandPaul House and Senate passed repeal in 2015. They should keep their promises and bring them up again for a vote now @RandPaul I demand the House release the text of the bill. Every elected official & every American deserve to know what they're trying to do @RandPaul I will not vote for Obamacare Lite nor will many of my colleagues. We will keep our word. I call on House leaders to do the same @RandPaul And I call on them to make this process transparent and to let the sunshine in. Today. .@randpaul wasn't allowed to see the House GOP's Obamacare bill. Brought his own copy machine, just in case. https://t.co/KpAXhfltsV .@RandPaul outside the "secret office for the secret bill." https://t.co/fY8BAVqwvd Up Next See Gallery Discover More Like This HIDE CAPTION SHOW CAPTION of SEE ALL BACK TO SLIDE

Those promises were a consistent part of Trump's presidential campaign.

And he's made it clear that he backs the new plan, calling it "wonderful" and saying he is "proud to support" it. But opposition will be fierce.

Senate Democratic leader Charles Schumer called the bill "a giveaway to the wealthy and insurance companies."

RELATED: Poll - Views on repealing and replacing Obamacare

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