Why a Debt Ceiling Bill That Will Never Become Law Has Kevin McCarthy Sweating

House Speaker Kevin McCarthy has been in a precarious position as leader ever since his marathon speakership vote in January, when the California Republican made a number of concessions to win over the 20 or so hard-right members of his party who opposed his bid.

A little more than 100 days later, his authority over the GOP is still fragile—and he’s about to face his biggest test yet as House Republicans prepare this week to vote on his bill to raise the debt ceiling temporarily and slash federal spending.

McCarthy and other top Republicans are hoping to get the bill on the House floor as early as Wednesday, but there is growing concern that they will be unable to muster the 218 votes needed to pass the $4.5 trillion package. Several Republicans have expressed discomfort with the bill’s energy and environmental provisions, while others are saying the work requirements McCarthy and others want to impose on federal social programs are too weak.

Just five Republican “no” votes would sink the bill if all 213 Democrats unite in opposition to the package. If McCarthy can’t deliver the votes this week, it could compromise his leverage in talks with Democrats, who have so far refused to negotiate with him on the debt ceiling, challenging him to prove he has the support needed to pass a proposal without their help.

With a slim margin for error, the pressure is mounting on McCarthy. “I think he is in an almost impossible position,” says former Democratic Sen. Kent Conrad, who served as Budget Committee Chairman from 2007 to 2013. Even though the bill wouldn’t pass the Senate, how the House ultimately votes on it will reveal the extent of McCarthy’s political power, after he battled his GOP detractors for 15 rounds of voting during a grueling, televised four-day spectacle for the Speaker’s gavel in January. A win for McCarthy would show that he can keep his narrow majority in line and pass a big piece of legislation amid simmering tensions. But a loss could derail his speakership and rattle the markets, sending an ominous signal about what to expect later this summer as the debt ceiling fight continues.

Read More: Previous Debt Ceiling Fights Offer Clues to How This One Will End

“He’s one false move from a motion to vacate the chair, so you see him really staggering around trying to find some solid ground on which to stand,” says Jim Kessler, former legislative director for Democratic Sen. Chuck Schumer before Schumer became Majority Leader. Any one member can force a House vote to overthrow the Speaker, as part of the concessions McCarthy made earlier this year.

McCarthy says the legislation—dubbed the Limit, Save, Grow Act of 2023—would preserve U.S. credit and slow the accumulation of debt, capping federal agency spending over the next decade to achieve more than $3 trillion in savings. It would also repeal key climate investments and impose new work requirements on recipients of federal aid, including Medicaid.

Already, a number of House Republicans have expressed their opposition to McCarthy’s bill. Rep. Tim Burchett, who represents a deep-red district in Tennessee, says he is “leaning no” on the package and is still wary about raising the debt limit at all. “It would make things easier for him to vote for the bill if all his demands were met,” his spokesperson tells TIME. Burchett wants to raise the threshold for federal aid work requirements from 20 to 30 hours a week, and would also like those work requirements to take effect sooner.

Rep. Matt Gaetz, the firebrand Florida Republican, expressed a similar stance on Monday evening. “An essential element to get my vote for any increase in the debt limit would be enacting work requirements starting in fiscal year 2024—NOT 2025 as the legislation is currently written,” Gaetz tweeted. “Otherwise, it’s a no vote from me.” Gaetz and several other Republican leaders, including Budget Chair Jodey Arrington and Ways and Means Chair Jason Smith, met with McCarthy’s team last Thursday to discuss the work requirements and get a feel for how the different factions of the party would vote.

Rep. Nancy Mace, a Republican from South Carolina, signaled that she will vote “no” on the bill because the green energy tax credit rollbacks would make it more expensive to build solar and wind power in her state. Leadership has made “no promises” to her, a Mace aide tells TIME.

Mace isn’t the only Republican with hesitations about the climate provisions of the package. McCarthy’s bill would roll back nearly two dozen clean energy and manufacturing tax credits from the Democrats’ Inflation Reduction Act (IRA), which every House Republican voted against last year. But the proposed elimination of ethanol and biodiesel tax credits within the IRA has been the main source of tension among Midwestern Republicans this year. The issue isn’t fading away, either. As many as 10 House Republicans could vote against the GOP package because it eliminates the ethanol tax credits, Punchbowl News reported Tuesday.

Rep. Jen Kiggans, a freshman Republican who represents a Virginia district that Biden narrowly carried in 2020, says she is still undecided on how she will vote, but is concerned over the bill’s rollback of wind energy tax credits. She spoke with Republican leadership over the weekend and they were “very responsive to her concerns,” a Kiggans aide tells TIME.

The House Rules Committee is scheduled to begin marking up the bill on Tuesday afternoon, a precursor to a floor vote that could happen as early as Wednesday. But even if McCarthy is able to push his debt limit bill to House approval this week, the legislation is dead-on-arrival in the Democratic-controlled Senate. No Democrats have expressed support for the plan, and President Joe Biden‘s office said on Tuesday that he would veto the bill if it ever made it to his desk. The GOP is instead using the bill as a political messaging tool to push for talks with Biden and serve as a legislative vehicle available on the debt ceiling as a potential default on U.S. debt looms.

The U.S. officially hit the debt ceiling last month, and as a result could face the prospect of default as soon as June if lawmakers and the White House do not strike a deal to raise the federal borrowing limit within the next two months.