The Obamacare replacement plan offered by congressional Republicans will face its biggest test yet when the House Budget Committee gathers Thursday to review the bill.

The 36-member panel will meet to vote on the proposal, called the American Health Care Act.

At least three conservative lawmakers who have spoken out against the legislation hold seats on the committee, however. Of the 22 Republicans on the panel, just four need to join Democrats in opposing the Obamacare replacement plan for it to fail.

The committee’s roster, plus the release Monday of the Congressional Budget Office’s report on the plan, only further call into question the future of the proposal from House Republican leadership.

CBO, a nonpartisan agency that works for Congress, found that under the bill, 24 million Americans would be uninsured by 2026 and premiums would rise 15 percent to 20 percent over the next two years before dropping by 10 percent in 2026, depending on a person’s age.

Thus far, the loudest voices speaking out against the Obamacare replacement plan belong to members of the House Freedom Caucus, a group of roughly 40 conservative lawmakers. They hope to negotiate with President Donald Trump, who backs the bill.

Three members of the Freedom Caucus serve on the Budget Committee: Reps. Dave Brat of Virginia, Gary Palmer of Alabama, and Mark Sanford of South Carolina.

A spokeswoman for Palmer told The Daily Signal the Alabama Republican is still looking at the legislation and the CBO report.

Palmer has “a few concerns and is hoping to have discussions about potential revisions,” she said.

Brat and Sanford both joined fellow Freedom Caucus members and Sens. Rand Paul of Kentucky and Mike Lee of Utah at a press conference last week to criticize the legislation.

“Do we need to lower the bar in what we believe as conservatives simply because a Republican is now in the White House?” Sanford, who called the plan an “opening bid,” asked.

Brat, meanwhile, was more direct as to the legislation’s fate.

In an interview with Fox News last week, the Virginia Republican said GOP leadership’s bill was dead on arrival in the House.

Brat also derided the proposal’s creation of refundable, age-based tax credits, which he and many other conservatives have panned for creating a new entitlement program.

“Right now, we are $100 trillion light on our promises,” Brat said, referring to unfunded liabilities. “Social Security and Medicare are insolvent currently. Guess who runs those? The federal government and politicians. I don’t think you want us running another entitlement program with your health on the line.”

While Brat said he doesn’t think the bill will pass the full House, just one more Republican opponent on the Budget Committee could stop it before it even makes it to the House floor.

Several lawmakers could emerge as the deciding vote.

Rep. Matt Gaetz, R-Fla., took to the House floor in January to criticize the Affordable Care Act, popularly known as Obamacare.

“I come to bury Obamacare, not to praise it,” Gaetz said in a speech. “What have my constituents gotten from Obamacare? Higher taxes, higher premiums, unaffordable deductibles, crippling drug costs, fewer choices, and more mandates.”

Gaetz also vocally opposed expansion of Medicaid eligibility under Obamacare while serving in the Florida House, which rejected the state Senate’s attempt to expand the program in 2015.

The House GOP’s Obamacare replacement plan would leave the Medicaid expansion in place until 2020.

Until then, expansion states could continue to enroll those newly eligible under higher federal matching rates. But after 2020, states that continue to sign up newly eligible residents would receive the traditional federal matching rate of 57 percent.

A spokesman for Gaetz told The Daily Signal the Florida Republican is reviewing the bill.

Rep. Tom McClintock, a Republican from California and former Freedom Caucus member, said last week he was “looking at” the Obamacare replacement plan.

In light of the report from the Congressional Budget Office, Rep. John Faso, R-N.Y., is “reviewing the legislation extensively” ahead of Thursday’s hearing, his spokeswoman told The Daily Signal.

Faso backs a “reform and fix” approach to Obamacare, and opposes defunding Planned Parenthood.

The Obamacare replacement plan crafted by House Republicans would place a one-year moratorium on federal funding for the organization, the nation’s largest abortion provider.

A GOP staffer on the Budget Committee told The Daily Signal that the hearing should produce a thorough review of the Obamacare replacement plan, but it is expected to clear the committee.

Though conservatives oppose the bill, many, like Sanford, hope to see it amended and have been pleased by Trump’s willingness to negotiate.

Many want the Medicaid expansion to be repealed quicker, and object to the tax credits. Conservatives also believe more of Obamacare, including the insurance regulations, should be repealed in the bill.

Rep. Joe Barton, R-Texas, last week proposed an amendment to the Energy and Commerce Committee that would repeal the Medicaid expansion by the end of the year. But the congressman ultimately withdrew it.

The Budget Committee doesn’t have the authority to make changes to the bill under the budget reconciliation process being used to advance it, the committee staffer said. But members can make motions, or recommendations, that the staffer said likely will reflect broader principles on what Republicans want to see in the final legislation.

If a motion passes the Budget Committee, Chairman Diane Black, R-Tenn., will take it to the Rules Committee—the next step in the legislative process—and recommend that panel allow for an amendment on the issue.

The GOP staffer said specific motions likely will be decided in the coming days.

The Budget Committee will be the third panel to review the Obamacare replacement plan, and it’s tasked with packaging it to form the reconciliation bill.

Last week, two other House committees took the first step toward repealing and replacing Obamacare after lawmakers on each panel passed their respective parts of the American Health Care Act.

The bills moved seamlessly through the Ways and Means and Energy and Commerce committees, and all Republicans on both panels voted to advance the legislation out of their respective committees.

Caleb Ecarma and James Rogers contributed to this article.