Republicans have 52 members in the Senate, which means they can afford only a couple of defections if they are to pass House Republicans' Obamacare replacement bill.

Sunday was not a good day on that front.

Here's what Sen. Rand Paul (R-Ky.) said on CBS: “Everybody’s being nice to everybody because they want us to vote for this, but we're not going to vote for it.”

And Sen. Tom Cotton (R-Ark.) on ABC: “I'm afraid that if they vote for this bill, they're going to put the House majority at risk next year. … I’m worried it could make it worse in some ways.”

And Sen. Dean Heller (R-Nev.) in an audio recording unearthed by Politico: “They’re talking about [getting rid of the Medicaid expansion by] 2020, now they’re talking about making the changes in 2018. That’s not enough time for Nevada to adjust.”

That's three very reluctant senators, two of whom spoke publicly about serious reservations. And none of them are even among the four GOP senators who have said they won't vote for anything that leaves millions uninsured. (We're still waiting for a Congressional Budget Office score that is very likely to show such a projection.)

The Trump administration and House Speaker Paul D. Ryan are defending the Republican bill to supplant the Affordable Care Act, while facing criticism from Democrats and fellow GOP lawmakers. (Bastien Inzaurralde/The Washington Post)

Republican leaders, including House Speaker Paul D. Ryan (Wis.) and President Trump, have expressed confidence that the bill will pass and warned of the dire consequences of not passing it. But it's clear from many Republicans' public comments that these words are falling on deaf ears. As The Fix's Amber Phillips notes, there are enough skeptical Republicans in both the Senate and the House to kill the bill right now, and many of them have spoken in quite strong terms, just like Paul and Cotton.

Ryan dismissed the rhetoric last week, suggesting it's the remnants of being a longtime minority party in Washington. “We’re going through the growing pains of being an opposition party with Barack Obama to actually being a governing party with a Republican President Donald Trump,” he told Hugh Hewitt.

But there is a difference between expressing a few reservations and the kinds of lines in the sand that are being drawn by the senators above. There is certainly something to be said for withholding support until you get something you want; these statements strongly suggest no adjustments — either moving the bill to the right to appeal to conservatives such as Paul and Cotton, or to the left to appeal to Heller and the group of four senators — are going to check the boxes for enough senators.

It's hard to overstate just how significant and wide-ranging the reservations are. Conservatives want the Medicaid expansion to be reined in sooner and the “Cadillac tax” to be cut. Middle-of-the-road senators, meanwhile, want the Medicaid expansion kept for a long time — if not permanently — and say they aren't going to abide by a decline in the insurance rate.

Satisfying either of those camps comes at the expense of the other. If the Medicaid expansion were ended sooner, how could Heller explain voting for it? And if it were extended, how would conservatives explain their hard-line rhetoric?

It's one thing to say the bill has flaws and you're worried about it; it's another to say that you won't vote for it — full stop — and that it could cost your party the House in 2018. And if the likes of Paul and Cotton stick to anything close to those postures, the bill is dead on arrival in the Senate.

Two weeks after introducing their bill to overhaul the Affordable Care Act to heated criticism, House Republicans unveiled amendments to the plan. Here's what you need to know about the legislation and its changes. (Bastien Inzaurralde,Sarah Parnass,Jenny Starrs/The Washington Post)