Donald Trump warned House Republicans in aclosed-door meeting Tuesday that many of them could lose theirseats in the 2018 elections if they don’t pass their bill toreplace Obamacare.

The president’s message came a day after GOP leaders madeseveral changes to their measure aimed at wooing reluctantRepublicans, including limits to Medicaid enrollment and an accelerated phaseoutof some taxes.

“Support it!” Trump told lawmakers, accordingto Representative Walter Jones of North Carolina, who said he stillopposes the measure. He said Trump’s remarks contained “nothing indetail, except politically it’s the right thing to do.” Trumpdidn’t take any questions from lawmakers.

Asked on his way into a closed-door GOP meeting whether they hadthe votes, Trump said, “I think so.” And Republican leaders voicedoptimism that the new changes would put them over the top when thebill reaches the House floor Thursday. A member of the Housevote-counting team said they’re getting closer to the 216 votesthey need for passage.

“The president just came here and knocked the ball out of thepark,” House Speaker Paul Ryan told reporters Tuesday. “He knockedthe cover off the ball.” He called the moment a “rendezvous withdestiny” for Republicans.

But House conservatives said late Monday that they didn’t getthe changes they were looking for and could block passage.

“Currently there are not enough votes to pass the legislation,”House Freedom Caucus Chairman Mark Meadows said Monday night aftera raucous caucus meeting. The group, which has opposed earlierversions, didn’t take an official position on the changes, but aspokeswoman said a whip count by the group showed it could defeatthe bill.

During Tuesday’s meeting, Trump singled out Meadows and jokedthat he’d “get there too,” according to Representative Fred Uptonof Michigan. Upton added that Meadows, red-faced, stood up andacknowledged the president.

After the meeting, Meadows said he’s still a no. "If this wasabout the president, I would have changed a long time ago," hesaid.

Conservative Republican Mo Brooks of Alabama also said he wasn’timpressed by Trump’s election threat.

“I think if we do vote for this we will lose the majority,”Brooks said after the meeting.

The alterations are being proposed to help add Republicansupport for the bill, which is set to come up for a vote on theHouse floor Thursday, and House leaders sounded an optimistic noteabout the chance for passage. The changes would allow states torequire people covered by Medicaid to work and block U.S. funds forany new efforts to expand the health program for the poor.

It isn’t clear yet whether the changes will persuade enoughRepublicans.

“I don’t know” if it will pass, said New York Republican PeterKing. “It’s going to be close.”

While it softens some measures that would make health coveragemore expensive for older people, the Obamacare overhaul remains athreat to hospitals and some insurers, which would see fewer payingpatients if it passed.

Wooing moderates

One indication that Ryan and his lieutenants are gainingimportant ground came late Monday when Representative Tom MacArthurof New Jersey and several other moderates said they would back thebill.

Related: White House wooing GOP holdouts on health plan maybackfire

MacArthur co-chairs a group of House centrists known as the"Tuesday Group." He was joined in his announcement byRepresentatives Tom McClintock of California, Martha McSally ofArizona and Robert Aderholt of Alabama. In a statement, thegroup pointed to adjustments to boost the bill’s tax credits forlower-income adults as key in helping to address theirconcerns.

Not all House moderates had yet joined in support by Tuesdaymorning, including MacArthur’s Tuesday Group co-chairman -- CharlieDent of Pennsylvania. But securing centrist backing is key for GOPvote counters, who have little wiggle room given ongoing oppositionfrom some conservatives.

“The bill will pass,” MacArthur said Tuesday.

But members had different opinions on whether the changes wouldbe enough to get it through.

“I think there are obviously some small tweaks that are goodtweaks but there’s no substantial changes in the manager’samendment that would make anybody be more compelled to vote forthis,” Meadows said Monday night.

‘Defining moment’

"This is a defining moment for the Freedom Caucus," he added. "Idon’t think there is a more critical vote for the Freedom Caucusthan this particular one."

Another Freedom Caucus member, Justin Amash of Michigan, saidhe’s confident the group will largely hold together to block thebill after leaders ignored their demands.

“We’ve made suggestions all the way through,” he said Mondaynight. “If they don’t want to listen to them then that’s onthem.”

House leaders were working hard to to win over remainingholdouts, both conservatives and moderates in their party, aprocess known as whipping votes.

‘A whip that’s 10 feet long’

“They’re already whipping with a whip that’s 10 feet long andfive feet wide,” Meadows said when asked if GOP leaders were tryingto pick off individual members of the Freedom Caucus.

An outcry followed the introduction of the GOP bill, which wouldcut assistance for people buying insurance, roll backthe Medicaid program for the poor and lead 24 million moreAmericans to be uninsured in 2026 than under Obamacare, accordingto one analysis.

Swelling numbers of people unable to pay their medicalbills would take billions of dollars out of the health-caresystem, pressuring hospitals, insurers and other health-carecompanies.

House leaders expect an updated analysis of the bill from thenonpartisan Congressional Budget Office before lawmakers vote onit, Ways and Means Chairman Kevin Brady told reporters Monday.

Ryan and his GOP lieutenants can afford to lose no more than 21votes in the chamber, presuming all Democrats vote against thebill.

Medicaid tweaks

The changes to the bill give states another option for how theirMedicaid payments from the federal government would be calculated.States could opt for block grant payments, instead of theper-person payment caps that were already in the measure. Theso-called manager’s amendment would also repeal Obamacare’s taxesthis year, one year earlier than originally planned.

Related: Poll shows Americans want Medicaidretained

Representative Chris Collins, a New York Republican, also toldreporters Monday that leaders agreed to add a special provision tohold $2.3 billion a year in Medicaid funding from New York unlessthe state’s governor and state legislature agree to stop forcingcounties to help pay for Medicaid. He said the change was needed tohelp persuade most New York Republicans in the House to back themeasure.

The Medicaid provision is written to pertain only to New Yorkcounties outside of New York City, said Representative John Faso, aco-author.

Lawmakers are also facing pressure from back home. Michigan’sRepublican governor, Rick Snyder, sent a letter to his state’sdelegation -- nine Republicans and five Democrats -- warning themof the law’s consequences in each of their districts. New York’sAndrew Cuomo, a Democrat, on Monday slammed some of the state’sRepublicans for supporting an amendment that could limit federalfunding of the state’s Medicaid program.

The changes didn’t include an alteration some conservative GOPmembers sought to wind down Obamacare’s expansion of Medicaidstarting in 2018 rather than in 2020 as was proposed in theoriginal legislation.

Some moderate Republicans also wanted to increase tax creditsfor older, poorer people -- a demographic that would paysubstantially more for health coverage under the GOP bill thanunder Obamacare. Those changes weren’t made in the most recentversion, but part of the amendment leaves room for the Senate toincrease the tax credits for that group.

Under the original legislation, older Americans would have beenhit with significant increases in premiums without adequatefinancial assistance. This new pot of money is created by a tweakto the bill that lowers the amount Americans can deduct from theirtaxes for the cost of medical expenses that exceed 10 percent oftheir income. The threshold would shrink to 5.8 percent.

The Medicaid limits are an appeal to more conservativeRepublicans. Most members of the Freedom Caucus want to go furtherand make it mandatory in all states, a GOP aide said.

Copyright 2018 Bloomberg. All rightsreserved. This material may not be published, broadcast, rewritten,or redistributed.