The leader of the largest group of House conservatives saidMonday he couldn’t support the party’s existing Obamacarereplacement strategy.

Related: GOP ACA plan would cover fewer people; blowbackgrows

Representative Mark Walker, who chairs the 170-member RepublicanStudy Committee, also said he won’t recommend his colleagues do so,either.

“There are serious problems with what appears to be our currentpath to repeal and replace Obamacare," Walker said in a statement,warning that the emerging GOP plan would appear to create a new,expensive entitlement program.

Walker’s announcement came a day before Donald Trump addresses ajoint session of Congress, and on the same day that the presidentpromised to offer “something special” on his health-care overhaulefforts.

But the comments from Walker are a potentially serious blow forthe plan by Republican leaders to push through a bill in the comingweeks to repeal and replace the polarizing health-care law.

Several conservatives have already voiced concerns about thestrategy not going far enough to dismantle Obamacare, while otherRepublicans have been battered by constituents in town halls overthe likelihood that the GOP’s replacement would insure fewerAmericans.

Related: Former GOP House speaker thinks ACA system willstay

The support of Walker, a North Carolina Republican, isimportant, given that the plan cannot be passed in the 435-seatHouse without almost unified Republican support, since noDemocratic backing is likely.

Outdated draft

Walker’s statement refers to a two-week old draft of theRepublican plan, leaked last week, which he said "risks continuingmajor Obamacare entitlement expansions and delays any reforms."

Related: Trump courts governors, health insurerCEOs

House Republicans are set to meet behind closed doors on Tuesdaymorning, where they are expected to discuss the path ahead. Manyleaders are counting on the strong pressure from outsideconservative groups pushing for a repeal to keep Republicans inline behind their plan, but the path forward remains difficult.

Trump’s administration has promised elements of a replacementplan by mid-March. But the president’s public statements havesometimes been at odds with GOP lawmakers. Trump has promisedbetter, less expensive care for all without cutting entitlementprograms, such as Medicare, while Republicans in Congress haveadmitted that their plan is likely to cover fewer of the 20 millionpeople who gained coverage under the Affordable Care Act.

‘Republican stamp’

Walker’s statement serves only to underscore that continued lackof cohesion.

“The bill contains what increasingly appears to be a newhealth-insurance entitlement with a Republican stamp on it," saidWalker, who had already been raising concerns over the proposedinclusion of refundable tax credits in the plan.

House Republican leadership favors that idea, but Walker said ina recent interview that conservatives believe "we’ve got to makesure we are not adding additional entitlement giveaways."

House Ways and Means Chair Kevin Brady said Monday that theleaked legislative language in question is "pretty outdated" in itsnumbers and that a lot of changes have been made.

But Brady declined to offer details on the new language beingconsidered, making it difficult to know whether the new proposalsare any more palatable to conservatives. Republican leaders haven’tabandoned the refundable tax credit, viewing it as necessary toprovide assistance to low-income Americans who have little or nonet tax bill.

‘Rubik’s cube’

"This is a continuous loop. We’re updating our drafts on almosta daily basis," Brady said. "So it is a little like turning aRubik’s Cube. We continue to bring specifications to them, theygive us feedback, we make adjustments, they give us feedback."

Asked what he’s learned from the process of trying to overhaulthe health-care system, Brady said: "This is enormously complicatedwork."

A wild card in the debate is Trump, who is expected to bring upthe issue during his joint speech to Congress on Tuesday evening.Trump has previously said he wants to insure everybody but hasrefrained from discussing policy details. He said earlier on Mondaythat he’ll soon release a "fantastic plan."

The president also seemed taken aback by the complexity of theendeavor.

"Nobody knew that health care could be so complicated," he tolda meeting of the National Governors Association.

Democratic unity

Walker’s announcement comes as Democrats in both chambers aregrowing increasingly confident that their strategy of unitingagainst a Republican alternative is working and that the inabilityof Republicans to coalesce around a replacement plan will doom theeffort.

“Republicans have not been able to pick off a single Democrat tosupport their plans,” Senate Minority Leader Chuck Schumer toldreporters Monday. “We have shown a united front, while Republicaninternecine warfare has been on full display.”

“I predict the discord in their party will grow as Republicansturn to Washington from this last week of angry town halls,”Schumer added. “I believe the odds are very high that we will keepthe ACA and it will not be repealed.”

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