House Republicans are sending a clear and early warning to their Senate allies as the bill encompassing President Trump’s domestic priorities heads to the upper chamber: Don’t water it down.

House GOP leaders spent weeks in delicate talks with Republican holdouts before cobbling together a fragile agreement that could thread the needle between conservatives’ demands for more spending cuts and moderates’ insistence on a controversial tax break.

As the massive package heads to the Senate, the critical voices of the House debate blue-state Republicans, hardliners and party leaders are cautioning their upper-chamber counterparts not to alter their design too severely, or it will never get through the House on its return.

The warnings forecast a coming clash between Republicans in the two chambers, since many senators are already saying they can’t support the package without substantial changes. 

House conservatives would be fine with some changes if they shift the bill to the right with more spending cuts and deficit reduction. At the bare minimum, they’re demanding that the Senate keep in place hard-fought provisions to limit Medicaid eligibility and roll back green-energy subsidies adopted by the Biden administration.

“They’ve got a lot they still need to do to make it better, and they can’t unwind what we achieved. And those are going to be red lines,” said Rep. Chip Roy (R-Texas). “If the SALT guys think they’ve got red lines, just wait until you see what’s coming out of us.”

Blue-state Republicans have their own concerns. They went to the mats to lift the $10,000 cap on the state and local tax (SALT) deduction, and they don’t want Senate Republicans to nibble away at their hard-earned victory. 

Their agreement included not only an increase in the cap to $40,000 for those making up to $500,000 but also commitments on how to handle the threat of any Senate changes. 

Unlike in the House, Senate Republicans do not represent regions where constituents are greatly impacted by the SALT deduction cap. For that reason alone, many Senate Republicans are cold to the notion of giving a bigger tax break to those who primarily have higher incomes and live in blue states.

Under the terms of the SALT Caucus deal, Speaker Mike Johnson (R-La.) committed to holding the line against any Senate changes. And the SALT Caucus members agreed to go to the Senate, at the Speaker’s request, to advocate for the higher deduction.

Rep. Nick LaLota (R-N.Y.), one of those core SALT Caucus members, echoed conservatives’ warnings to senators not to change the bill.

“House Members like me respect the Senate’s prerogative to shape key aspects of the One Big Beautiful Bill, but we respectfully request that Senators preserve the interlocking provisions that were carefully negotiated through months of tough internal deliberation,” LaLota said. “The bill’s strength and viability depend on maintaining that hard-earned balance.”

The precarious nature of the agreement is very much on the radar of House leaders, who are delivering their own unsubtle message to the Senate as the upper chamber prepares to deliberate the bill. 

Johnson huddled behind closed doors with Senate Republicans on Tuesday, during a traditional weekly lunch. Afterwards, he said he practically pleaded with the group not to make huge changes to the House design. 

“I encouraged them to remember that we have a very delicate equilibrium that we’ve reached over here. A lot of work went into this to find exactly the right balance,” Johnson said. 

“You saw how perilous that was over the last week as it developed,” he continued. “And I encouraged our Senate colleagues to think of this as a one-team effort, as we have, and to modify this as little as possible, because it will make it easier for us to get it over the line, ultimately, and finished and get it to the president’s desk by July 4. 

“That’s a big thing.”

House Republicans are quick to acknowledge that some Senate changes are inevitable even welcome. 

Rep. Don Bacon (R-Neb.), for instance, said the House bill leaves some confusion about whether refugees in the country legally can qualify for food assistance benefits under the bill’s reforms to the Supplemental Nutrition Assistance Program (SNAP), and he hopes that the Senate clarifies. Major changes, though, would be more problematic. 

In an early sign of trouble for House Republicans, a number of GOP senators are already rejecting parts of the lower chamber’s bill an indication that the package could return to the House in an entirely different form, which would likely spark a revolt from one wing or another.

“I think there will be considerable changes in the Senate,” Sen. Ted Cruz (R-Texas), the chair of the Commerce Committee, said this week, specifying that the tweaks will likely be “across the board” in the measure.

Republican senators are already voicing their dismay with the SALT provision included in the bill. New York, New Jersey and California the three states most concerned by SALT are completely represented by Democrats in the Senate, leaving the issue with no GOP champions in the upper chamber.

“There’s not one Republican in the United States Senate who gives a s— about SALT,” Sen. Kevin Cramer (R-N.D.) said. “Having said that, what does matter is 218 votes in the House, and we want to be cognizant about that.”

Some senators are also eyeing changes to the Medicaid language in the House bill. The legislation beefs up work requirements for able-bodied individuals between the ages of 18 and 65 and institutes more frequent eligibility checks, among other provisions.

The Congressional Budget Office (CBO) estimated that the bill would result in 10.3 million people losing Medicaid coverage by 2034 and 7.6 million people going uninsured, prompting concerns among some Senate Republicans. That review was released before the House expedited the implementation of the work requirements.

Sen. Josh Hawley (R-Mo.) has been most vocal about the worries pertaining to Medicaid, writing in a New York Times op-ed earlier this month that Medicaid cuts are “both morally wrong and politically suicidal.”

Sens. Susan Collins (R-Maine), Lisa Murkowski (R-Alaska) and Jerry Moran (R-Kan.) have also noted concerns about changes to the social safety net program, which further suggests the Senate is ready to shift the legislation to the center, not the right.

Trump, who intervened at the last minute to get the House bill passed, remains a wildcard in the Senate debate. But a source close to the White House noted that there’s a short list of GOP senators including Collins, Murkowski, Hawley and Mitch McConnell (R-Ky.) who can steer the direction of the bill on behalf of others without feeling pressured by Trump.

“A group of them are going to say, ‘Hey, we’re not going to just bow down to these things, which we believe are draconian, right?’” the source said. “They’re going to be a problem for our constituency, but more importantly, our colleagues.”

Senate Republicans can afford to lose only three of their own and get the legislation over the finish line. And they are already down to two: Rep. Rand Paul (R-Ky.) said he is a hard no on the House bill unless it removes the $4 trillion debt limit hike an unlikely scenario as a summer default looms.

“It’s not conservative; I can’t support it,” Paul said.

As House Republicans warn against changes to their preferred provisions in the bill, some of the same voices are holding out hope that whatever product returns from the Senate to the lower chamber will be more conservative an aspiration that is sure to leave them disappointed as Senate Republicans push to bring the package more towards the middle.

Roy, for example, said he voted for the bill despite “significant reservations,” noting that it needs “massive improvements.”

Rep. Andy Harris (R-Md.), the chair of the conservative House Freedom Caucus, echoed that sentiment, arguing that the Senate can make inroads in areas that the upper chamber is already looking to water down.

“I’m hoping the Senate can address the two issues that I think still are there,” Harris said. “One, the early deficit increases in the 10-year window. And the other one is getting at more of the fraud, waste and abuse in Medicaid.”

But if the Senate tries to weaken the legislation, he warned, all bets are off.

“We’ll reconsider our support,” he told reporters of such a scenario.

Alex Gangitano and Al Weaver contributed reporting.