When House Republicans passed the American Health Care Act on May 4, President Trump bullishly predicted that the bill would pass the Senate and arrive at his desk to be signed into law — though the timeline for the bill's passage is unclear.

“We're going to get this passed through the Senate,” he said, surrounded by beaming GOP congressmen. “I feel so confident.”

He followed his prediction up with (of course) a tweet Sunday morning:

But actual Republicans in the Senate seemed less confident, saying there will probably be major changes to the House bill — and that a vote might not come quickly.

There are a few reasons for that. First, Senate Republicans who are up for reelection in 2018 know that health care is a political minefield; they're probably keeping a wary eye on House Republicans who are facing angry constituents at town hall meetings while the House is in recess this week. Casting a vote for the current legislation, at a time when voters are paying close attention, could be a bad move with just 18 months to go until the next election.

Second, the GOP has a thinner margin in the Senate — just a 52-to-48 advantage over Democrats — than it does in the House, and the American Health Care Act was repeatedly derailed by House Republicans in the Freedom Caucus, a conservative group, and the Tuesday Group, a collection of moderate Republicans. Senate Majority Leader Mitch McConnell (R-Ky.) can only afford to lose the vote of two members of his caucus (which would then allow Vice President Pence to cast a tiebreaking vote). Remember, Republicans don't need to work with Democrats on this bill because they hope to pass it using the reconciliation process — a procedural maneuver that allows the Senate to make limited changes to budget bills passed in the House.

But that still doesn't leave much margin for error. Senate Majority Whip John Cornyn (R-Tex.) will have his work cut out getting the 51 votes Republicans need to pass the bill.

In the video above, and the list below, you can see what Republican members of the Senate have said about the version of the bill Senate Republicans hope to pass.

What Senate Republicans are saying

Senate Majority Leader Mitch McConnell (Ky.): “I commend the House and the administration for making this important advance last week. Now the Senate will do its work. The administration will continue doing its part to deliver relief and stabilize the health markets as best it can. This process will not be quick or simple or easy, but it must be done. It’s the least members in both parties owe countless Americans who continue to suffer under Obamacare, and the countless more who will be hurt if we don’t act.”

Senate Majority Whip John Cornyn (Tex.), when asked about a timeline for a Senate bill: “No timeline.”

Sen. John Thune (S.D.): “We will undertake work to try and produce a bill through the Senate that we can go to conference with in the House or get back to the House and be able to put something on the president's desk. … We want to make sure in the end that we get this right rather than getting it fast,” Thune said. "… The Senate will take its time and we will look at the House product and look for ways that we can strengthen it and improve it and ultimately, get something to the president that will have a desired effect and that's a more competitive insurance market.”

Sen. Susan Collins (Maine): “First of all, the House bill is not going to come before us. The Senate is starting from scratch. We're going to draft our own bill, and I'm convinced that we're going to take the time to do it right. Speaker Ryan today said that he hoped the Senate would improve the House bill. I think that we will do so and we will come up with a whole new approach.”

Sen. Bill Cassidy (La.): “You can cut premiums, but it has to pass the 'Kimmel test.' Jimmy rushed his son over to have surgery. Now, I take that as a metaphor — is your policy adequate? Of course you can cut premiums if you do — it sometimes happened under Obamacare, people got a so-called 'skinny policy.' We need to have something that is cheaper than an Obamacare policy but still has adequate coverage, so that if somebody has a crisis, they have the coverage.

Sen. Dean Heller (Nev.): “We cannot pull the rug out from under states like Nevada that expanded Medicaid, and we need assurances that people with preexisting conditions will be protected.”

Sen. Lindsey O. Graham (S.C.):

Sen. Roy Blunt (Mo.): “I think what's happened is not dead on arrival, not taking the House bill and bringing it immediately to the floor, but taking what the House was able to do, looking at that carefully, and coming up with what the Senate thinks the Senate can do. You know, this is the way legislation used to be passed: There'd be a House bill, there'd be a Senate bill, you'd get together, the conferees who understood by that time the intricacies of what they're doing, and come up with a bill that can go to the president's desk, and I hope that's what we do here.”

Sen. Shelley Moore Capito (W.Va.): “We’re going to be talking about Medicaid. That’s the issue I’m concerned about.”

Sen. Lisa Murkowski (Alaska): “My concerns regarding health-care reform haven't changed — it must work in a state like Alaska and not pull the rug out from those who currently receive coverage. And while we work to fix the broken current health-care system, I recognize the need to maintain provisions that have worked: The prohibitions on discrimination for preexisting conditions, no annual or lifetime limits, coverage up to age 26, and Medicaid expansion.”

Sen. Rob Portman (Ohio): 

This post will be updated.