WASHINGTON -- President Trump praised the new Republican replacement for Obamacare as “wonderful” on Tuesday. But it was a dead letter to conservative Republicans who said that it broke promises that they made to voters.

Mr. Trump said last week, “nobody knew healthcare could be so complicated.” Turns out the same is true about Capitol Hill.

Mr. Trump led a party-wide sales pitch on Tuesday aimed at fellow Republicans.

“I think, really, that we’re going to have something that’s going to be much more understood and much more popular than people can even imagine,” he said.

Conservative lawmakers understand it, but some of them they just don’t like it.

“Obviously we have some serious concerns,” said Rep. Mark Meadows, R-N.C.

They’re balking at the bill’s tax credits, which are designed to help low and middle income Americans buy insurance. The credits range from $2-14,000 a year, depending on age and family size.

Rep. Mark Meadows, R-North Carolina. CBS Evening News

Kentucky’s Rand Paul called it “Obamacare lite.”

“We are united on repeal but we are divided on replacement,” Paul said.

Republican leaders pushed back, noting that the plan meets party goals like scrapping the individual mandate and repealing taxes on the health care industry.

“It takes power out of Washington. It takes power out of the bureaucracy, and puts it back to doctors and patients where it belongs,” said House Speaker Paul Ryan.

But some key details are still missing, like how much the new bill will cost.

“How are you telling your members that this bill will be paid for?” CBS News asked Senate Majority Leader Mitch McConnell, R-Kentucky.

“Well it just got launched yesterday,” McConnell said.

“But isn’t that pretty integral? I mean if you don’t pay for the plan with taxes, what are the alternatives?” CBS News asked.

“As I said, we’ll be looking at the whole proposal here,” McConnell said. “We’ll have ample time to answer all the questions.”

I feel sure that my friend @RandPaul will come along with the new and great health care program because he knows Obamacare is a disaster! — Donald J. Trump (@realDonaldTrump) March 8, 2017

Republicans will need near-unanimous GOP support. So on Tuesday, Vice President Mike Pence met with the skeptics.

“We’re certainly open to improvements and to recommendations,” Pence said.

There will be no sales pitch to Democrats, who made it clear on Tuesday where they stand.

“Well Trumpcare is here and you are going to hate it,” said Sen. Chris Murphy, D-Conn.

Democrats argue older, lower-income Americans will hate it more than anyone. Some of them could see their Obamacare credits cut in half, even as the wealthiest Americans enjoy a series of tax cuts under this plan.