President Donald Trump caused a stir when he suggested Sunday that the Republican Party's quest to repeal and replace the Affordable Care Act might continue through 2018. But some Republicans think he might be on to something.

"I know there was some hyperventilating about the president's comments that this could spill into next year, but that didn't bother me," Rep. Charlie Dent, R-Pennsylvania, said as he left a caucus meeting Tuesday. "I thought it was fairly realistic."

"I do think slowing down would be wise," Rep. Tom MacArthur, R-New Jersey, told NBC News when asked about Trump's comments.

Trump's remarks come as efforts to repeal and replace the Affordable Care Act, which began with a bang after the election, are lagging amid internal debates over the substance of a Republican health care plan and the process used to pass it.

The current plan is a delicate multi-step path that requires Republicans to use the budget reconciliation process to partly repeal Obamacare by a majority vote and install some elements of a Republican plan, then negotiate with Democrats later on a full replacement, which would require 60 Senate votes.

Republicans can't manage many defections — they have only 52 votes in the Senate — and consensus has so far been elusive.

On one hand, conservatives are eager to fulfill the Republican Party's longtime promise to repeal the law and replace it with a less expensive plan with fewer taxes and more free-market principles.

On the other hand, more moderate Republicans are concerned that removing too much of the law too fast could wreck the insurance market and that some conservative plans to replace it could leave too many Americans without coverage.

Several key Republicans in the Senate have backed a bill that would give states an option to keep Obamacare's basic structure in place if they choose. Those Republicans are being pressured on two fronts — from Democrats back home who have been energized by Trump's election and conservative activists concerned that GOP leaders are slow-walking repeal.

Rep. David Brat, R-Virginia, a conservative economist who upset former Majority Leader Eric Cantor in 2014, said his colleagues needed to ignore the angry protests, which he described as "AstroTurf" efforts by established liberal groups, to reach the light at the end of the tunnel.

"What we've heard from Scott Walker and people who have done reforms in their states is that the biggest danger is not going through with the reforms," he said. "You can't halfway reform." Walker, the governor of Wisconsin, has fought pitched battles with unions in the past over state program reforms.

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To MacArthur, however, the bigger risk is leaping without looking first. He said the number one goal should be "stability" for those who have coverage, and he recalled that Democrats paid a stiff price for trying to do too much at once with their own health care bill.

"My fear is we're only human, too. We could make the same mistake," he said. "So I think we should slow down, I think we should get it right, and I think we should make sure we don't inadvertently hurt millions of Americans who are depending on it."

Republican leaders reassured skeptics on Tuesday that things were still on track after Trump made somewhat ambiguous comments on health care on Sunday. He may have been referring to when repeal takes effect, which could come years after passage, rather than the legislation itself.

"I think there's a little confusion here," Speaker Paul Ryan, R-Wisconsin, said Tuesday. "The legislating is going to be done this year. We are going to be done legislating with respect to health care and Obamacare this year. The question is how long does it take to implement the full replacement of Obamacare."

White House Press Secretary Sean Spicer told reporters that the president is "optimistic about getting this thing completed by this year."

But the president's tone has changed. Before the election, he called for a special session of Congress to repeal Obamacare "immediately," and top aide Kellyanne Conway suggested after he won that it might even happen on Inauguration Day.

Shortly before taking office, Trump told The Washington Post that he had a plan to provide "insurance for everybody" and that it was "down to the final strokes."

Sunday, however, Trump said that it "maybe it'll take until sometime into next year" and that the process was "very complicated."

Other pressures are looming that could make inaction difficult, as well.

The individual insurance market created by Obamacare is struggling, with some major insurers pulling out after taking losses and others raising premiums by significant amounts. Insurers will submit bids for plans on next year's exchange as soon as April, and industry leaders are warning Congress that they need clarity on the repeal process soon before they make any decisions.

"Even if you're going to delay replacement until later, they need to know ... what the rules are, what the boundaries are, what the expectations are as to what these plans should look like," Sheryl Skolnick, a health care analyst at Mizuho Securities USA, told NBC News. "Right now, there's no visibility."

Rep. Hal Rogers, R-Kentucky, who sits on the powerful Appropriations Committee, said it was "unlikely" that Congress could complete a health care plan by Ryan's April deadline. But he warned that inaction could be dangerous, as well.

"We got to do it right. At the same time, we need to do it as quickly as we can, because the present system is collapsing," he said.

Dan Mendelson, chief executive of the consulting firm Avalere Health, suggested that the White House might be able to hold things over while Congress drags on by making some administrative fixes to prop up the insurance market.

"They don't want to see an implosion," Mendelson said of the White House. "They're aware of the issues, and my expectation is they will take them very seriously in the coming weeks."

Trump's pick to lead the Department of Health and Human Services. Rep. Tom Price, R-Georgia, has still not been confirmed, which Republicans complain has slowed things down.

There are even more issues, as well.

Because Republicans are relying on an obscure parliamentary technique to pass repeal by a bare majority, they have less flexibility on timing. The budget reconciliation process that they've slated for Obamacare repeal will expire when they move on to reconciliation for next year's budget — which they've already reserved as their vehicle to pass corporate tax reform.

If health care repeal stalls, they might have to pull off tricky legislative maneuvers to buy more time, or they might have to try to accomplish tax reform and health care together in one bill.

"It's going to get more difficult, not less difficult," Stan Collender, a veteran former budget aide who is now executive vice president of Qorvis MSLGROUP, told NBC News.

As for Democrats, the strategy appears to be to wait the Republicans out. The idea is that as repeal efforts drag on, Republican leaders might be tempted to cut a deal on a modest bill that would shore up Obamacare's insurance market rather than risk a long fight over more sweeping changes.

"I'm hopeful there will be enough Republicans to join the Democrats and talk about some improvements," said Sen. Dick Durbin, D-Illinois. "Sign me up — once you take repeal off the table."