The fate of President Donald Trump’s legislative agenda now rests with the U.S. Senate, where a handful of Republicans are pushing for changes to the massive $5 trillion GOP tax and spending bill.

The legislation, officially titled the One Big Beautiful Bill Act, slashes spending on social programs like the Supplemental Nutrition Assistance Program and Medicaid, while proposing trillions in tax cuts and billions in investments to strengthen defense and border security. According to an analysis from the nonpartisan Congressional Budget Office, the legislation would kick nearly 8 million people off their Medicaid health insurance over 10 years, in part by making it more difficult to qualify for the program. It would also result in an estimated 3.2 million Americans losing their food assistance due to stricter eligibility requirements.

Republicans are rushing to pass the bill in both chambers of Congress and send it to Trump’s desk by the July 4 holiday, an ambitious timeline given outstanding concerns raised by several Republican senators over its significant impact on the deficit, its repeal of renewable energy tax credits passed by Democrats in the 2022 Inflation Reduction Act, and its severe cuts to Medicaid, a program relied on by 70 million Americans, including many Trump voters.

GOP leadership can afford to lose support from no more than three Republicans in order to pass the legislation with a simple majority of votes under a special budgetary process called reconciliation.

Here are five GOP senators to watch as the Senate tackles the bill this month:

Ron Johnson

Sen. Ron Johnson (Wis.) has been making the case for months now that the House bill fails to address the country’s worsening fiscal situation. The conservative senator is pushing for far more spending cuts to be included in the final product — more than $6 trillion. He says those are needed to return to an appropriate pre-COVID-19-pandemic spending baseline.

“I think the House did a lot of good work. I think we need to go further,” Johnson told reporters on Monday. “I support the president. I want to see him succeed. But again, we’re not going to do what we need to do if it’s just one big bill. We don’t have the time.”

Johnson added that he wants some kind of commitment for longer-term action to address the deficit and to “keep pressure on the system.”

Including interest, the House bill would balloon the nation’s debt by $3.1 trillion, even when accounting for its $1.5 trillion in safety net cuts, according to an analysis by the Committee for a Responsible Federal Budget. It would add $5 trillion to the debt over the next decade if its tax breaks for businesses are made permanent, a key goal of top Senate Republicans.

Rand Paul

Sen. Rand Paul (Ky.) has called the $5 trillion debt limit increase in the House bill a deal-breaker for him, pointing out that it would be the largest-ever one-time increase in the statutory borrowing ceiling.

“We have never raised the debt ceiling without actually meeting that target,” Paul told reporters on Monday. “So you can say it doesn’t directly add to the debt, but if you increase the ceiling $5 trillion, you’ll meet that. And what it does is it puts it on the back burner. And then we won’t discuss it for a year or two.”

“I’ve told him I can’t support the bill if they’re together,” Paul said after a phone call with Trump on Monday. “If they were to separate out and take the debt ceiling off that, I very much could consider the rest of the bill.”

Republicans for years opposed such debt limit increases, taking the nation’s fiscal health hostage by demanding equal spending cuts from Democrats. Under both of Trump’s presidencies, however, they’ve looked the other way.

“The GOP will own the debt once they vote for this,” Paul warned in an interview with CBS News on Sunday.

Josh Hawley

Sen. Josh Hawley (Mo.) has been vocal in opposing what he sees as cuts to Medicaid that could close rural hospitals, including in his state of Missouri, which expanded Medicaid under the Affordable Care Act. He wants to undo the House bill’s changes to so-called provider taxes, which most states use to help finance their share of Medicaid costs, and new copayment requirements for some beneficiaries that he has dubbed a “sick tax.”

“Why would we risk putting more rural hospitals in Missouri ― we lost like a dozen rural hospitals in the course of just a few years ― I mean, why would we want to risk that?” Hawley said Monday.

The Missouri Republican also spoke with Trump on Monday, telling reporters that the president agreed with him on not cutting Medicaid benefits.

“I said to him, when he asked me, ‘What do you think the prospects are of passage in the Senate?’ I said, good, if we don’t cut Medicaid, if we do no Medicaid benefit cuts. And he said, I’m 100% supportive of that,” Hawley said.

But Hawley said he has no qualms with imposing additional work requirements for Medicaid recipients that would cut benefits entirely for nearly 8 million people, per the CBO.

Susan Collins

In addition to voicing similar concerns about reductions in Medicaid spending, Sen. Susan Collins (Maine), a key moderate up for reelection next year, has signaled skepticism alongside Sen. Lisa Murkowski (R-Alaska) over language in the House bill banning Planned Parenthood from receiving any sort of federal funds.

The GOP bill would eliminate all funding to Planned Parenthood and other reproductive health care providers for a period of 10 years. Paired with the major cuts to Medicaid, it would further decimate access to maternal health care.

“Medicaid is the largest payer of reproductive health care, including maternal health care, in the country,” the Center for Reproductive Rights noted last month. “It is critical to ensuring that millions of low-income Americans can access essential sexual and reproductive health care through the provider of their choice. Defunding providers like Planned Parenthood would eliminate that choice and targets communities who are already facing barriers to care.”

Thom Tillis

Sen. Thom Tillis (N.C.) is one of four GOP senators who has urged party leadership against broadly gutting renewable energy tax credits that Democrats passed in President Joe Biden’s Inflation Reduction Act. The House bill would sharply restrict the option for clean energy sources like wind and solar to claim the tax credit, a move that would cut spending but increase energy costs for consumers and cost tens of thousands of jobs across the country.

That’s why some Republicans in the Senate want to change how quickly the legislation phases out the tax credits for renewable energy construction, preserving them for some projects.

“What we’re trying to focus on is to make sure that if businesses have invested and have projects in progress, that we do everything we can to hold them harmless,” Tillis, who faces reelection next year, told reporters Monday.