House leaders and President Trump are still scrambling to shore up support for the GOP’s health reform bill in advance of a decisive floor vote later this evening.

As of Wednesday night, Speaker Paul Ryan (R-WI) appeared to be short of the 215 votes he needs to get the bill passed. Trump is trying to win over members of the conservative Freedom Caucus, who oppose the bill, in a meeting at the White House today. Conservatives say they want a provision added to the bill to eliminate a mandate that insurance plans provide a minimum menu of “essential health benefits.”

The essential health benefits mandate is part of the Affordable Care Act and was intended to require insurance companies to provide coverage in 10 areas, including mental health, maternity care and prescription drugs. The Freedom Caucus argues that the requirements drive up premium costs and that consumers should be able to pick cheaper plans if they determine they don’t need certain benefits. The White House agreed to the concession last night.

It’s not clear, however, whether getting rid of the essential health benefits mandate will be enough to win over conservative skeptics of the House bill. Ryan also has problems with moderate Republicans who were not impressed with the Congressional Budget Office (CBO) score of the bill. CBO projected last week that 24 million fewer Americans would have insurance over the next 10 years under the GOP plan.

Ryan was still trying to play to different audiences last night, saying he’s willing to negotiate but that doing nothing to replace Obamacare is not an option.

“We are in the fourth quarter of the House passing this bill, which is the fourth committee,” Ryan said. “Now that we’re getting to the fourth committee of a four committee process, that’s when a lot of negotiations really intensify, near the end of the process. And that’s what this is – this is called legislating.”

Should the House pass the bill tonight – which is far from certain – it would likely encounter major problems in the Senate without changes. Repeal of the essential health benefits wouldn’t be permissible under Senate reconciliation rules, according to a spokesperson for Senate Minority Leader Chuck Schumer (D-NY).

“It will require 60 votes to repeal these protections, and the votes just aren’t there in the Senate,” said Matt House, a spokesperson for Schumer, in an interview with The Hill.

Earlier this week, the House was able to pass a separate bill that would empower small businesses and individuals to join together through association health plans to purchase group health insurance. The Small Business Health Fairness Act (H.R. 1101) passed the House by a 236-175 vote. Association health plans (AHPs) have long appealed to small businesses and individuals looking to lower their premiums and achieve some of the same purchasing power of larger employers. The bill’s sponsors, Rep. Sam Johnson (R-TX) and Rep. Tim Walberg (R-MI), say that having one set of federal standards for AHP coverage and exempting AHPs from state insurance laws could make them part of the plan to fix the healthcare system.