President Donald Trump’s statement over the weekend that a Republican replacement for the Affordable Care Act won’t be done until late 2017 or early 2018 is the latest sign of trouble for the GOP’s legislative agenda on health policy, tax cuts, and other priorities.

Asked by Fox News’ Bill O’Reilly whether his administration will roll out its health plan this year, Trump said “maybe it’ll take sometime into next year… Very complicated – Obamacare is a disaster… I think that, yes, I would like to say by the end of the year, at least the rudiments, but we should have something within the year and the following year.”

Some observers welcomed Trump’s statement as his belated recognition of the reality of the cumbersome legislative process. They argued it gives congressional Republicans political permission to slow down and craft a more workable replacement plan — even though House conservatives are demanding swift and total repeal with or without a replacement ready.

But others said the president’s words signal that the GOP repeal-and-replace train could be headed for a train wreck.

“It’s a political disaster for the ‘repeal and demolish’ crowd,” said Lawrence Jacobs, an expert on healthcare politics at the University of Minnesota who generally supports the ACA. “Delay allows the opposition to grow and strengthen, and every day that passes moves the GOP closer to the 2018 election and the prospect of Republican congresspeople and governors facing voters with the bad news that the health benefits they had are now gone.”

Trump and congressional Republican leaders originally planned to repeal the ACA early this year and pass a replacement package by early or late summer. Trump recently said his administration had a plan that was near completion. House Speaker Paul Ryan has set a new timeline of repealing the law through an expedited budget reconciliation process, on a straight party-line vote, by late March or early April, with replacement legislation following within a few months.

But Republicans now are confronting the daunting complexity of health policy, total opposition from Democrats, and unexpectedly strong resistance to repeal from the public. At constituent forums in their districts, a number of House Republicans around the country have faced large, angry crowds attacking them for supporting ACA repeal.

And at least six Senate Republicans, wary of ending the ACA’s coverage expansions and leaving 20 million Americans uninsured, have said they won’t vote for repeal without having legislation ready to replace the ACA’s coverage.

Meanwhile, insurers, hospitals, and other healthcare stakeholders have warned Republicans that they will throw the individual health insurance market and provider finances into chaos if they don’t establish a solid ACA substitute at the same time they abolish the law.

Trump’s statement is “a ratification of the underlying reality Republicans all are adjusting to,” said Tom Miller, a conservative health policy expert at the American Enterprise Institute. “Shock and awe and rapid action doesn’t have the votes. Trump acknowledged that speed is not of the essence.”

But lack of speed in developing and passing an ACA replacement package may cause headaches for the healthcare industry, which wants to know the new rules of the road as soon as possible.

“Additional time to develop a thoughtful, comprehensive alternative approach to healthcare is fine as long as out leaders quickly bring some clarity to the transition period,” said Ceci Connolly, CEO of the Alliance for Community Health Plans, which represents not-for-profit insurers. “The current uncertainty threatens to drastically destabilize the market.”

Slowing down also could suck the oxygen out of other Republican legislative priorities such as tax reform, Medicare restructuring, immigration curbs, and regulatory reform. Ryan said last week that tax reform must wait until after Congress repeals the ACA through budget reconciliation. But if Republican senators refuse to vote for repeal until a replacement package is ready – and no replacement package surfaces until late this year – tax reform will be on indefinite hold.

“I’m not getting nervous, but ACA repeal-and-replace has slowed down more than I thought it would,” said Chris Condeluci, a healthcare lobbyist who served as a Senate Republican aide during the passage of the ACA. “If Republicans continue to run into resistance back home, they’ll pivot to a different legislative strategy and put repeal-and-replace on the backburner.”

If repeal-and-replace gets pushed back, “you start crowding the inbox,” Miller said.

The Republicans’ biggest problem may be their own divisions over healthcare. The hard-right members of the House Freedom Caucus, who want full repeal with little or no replacement coverage, and a bloc of more pragmatic senators, who would prefer an Obamacare-lite approach, may not be able to reach a compromise.

The two factions previously battled in 2013 over whether to include ACA repeal in legislation to raise the deficit ceiling. That contributed to a standoff between the House and Senate, shutting down the federal government for 16 days.

“The odds are that the Republicans will pass some significant changes to the Affordable Care Act,” Jacobs said. “But there is a chance they’ll get stalemated. We’ve seen this car crash before.”