The implosion of the Senate Republicans’ health-care ambitions leaves the Affordable Care Act intact for the moment – but immediately creates worrisome unpredictability for the 10 million Americans who buy health plans through the law’s insurance marketplaces.

These consumers could face a rocky few months, at the least, as the insurers on which they rely decide how to respond to the political chaos. Some companies could become more skittish about staying in the marketplaces for 2018, while others could try to ratchet up their prices depending on how events in Washington unfold.

With his bill doomed late Monday, Senate Majority Leader Mitch McConnell, R-Ky., proposed a short-lived alternate path that would have repealed parts of the sprawling 2010 law and effectively would have wiped out its requirement that most people carry coverage. Insurers have long feared an end to that mandate, arguing that the marketplaces work only if everyone is insured.

Lacking clarity from Congress, the White House’s powers over the nation’s health policy loom large and murky. Although President Trump on Tuesday reiterated his intention to “let Obamacare fail,” he has not yet made two critical decisions.

Most immediately, the administration has the power to decide whether to halt the billions of dollars in payments to health plans that help their lower-income ACA customers afford deductibles and other coverage expenses. Those cost-sharing subsidies benefit 7 million Americans. The president could turn off the spigot by dropping an appeal of a federal lawsuit filed by the House over the payments’ legality.

The other decision is whether to ease off enforcement of the ACA’s penalty for Americans who shirk the coverage mandate. Trump cannot end the mandate without a change in law, but the Internal Revenue Service recently said it would continue to process refunds even when taxpayers flout a requirement to file proof that they have health coverage. The administration could go further.

“We are still considering our options,” White House spokesman Ninio Fetalvo said.

The disarray in the Senate and the ambiguity in the administration “just continues the sort of volatile environment,” said one insurance industry official, speaking on the condition of anonymity because of the political sensitivities. “It’s adding uncertainty to what was already an uncertain climate.”

The Senate’s stalemate – with Republicans, who hold the majority, seeing a way neither to rewrite the health-care law nor to end a repeal drive that has been the party’s guiding aspiration for years – comes at a particularly critical time of year for the ACA’s marketplaces.

Participating insurers already have filed the rates they plan to charge in 2018 with state agencies and federal health officials. In fact, some have submitted two sets of prices to account for whatever happens with those subsidies – and may need to make a choice before the president makes up his mind.

In early August, the 2018 rates are scheduled to be published by the federal Centers for Medicare and Medicaid Services. And in late September, the insurers selling health plans for next year must sign contracts with the government.

Less than four months away is the start of the next enrollment season for new and returning customers.

The willingness of insurers to sell plans on the marketplaces, intended for people who cannot get affordable health benefits from a job, is one of the linchpins responsible for the drop in the ranks of the uninsured since the marketplaces opened in 2014.

Republicans, including Trump, have long contended that the exchanges are collapsing. They have pointed to insurance rates that spiked in many places this year and threaten to do so again in 2018, as well as the defection of several of the nation’s largest insurers.

Yet other evidence suggests that Republicans’ determination to tear apart the ACA comes, ironically, as the marketplaces are finding stability. A study released this month by the Kaiser Family Foundation analyzed two measures of the financial health of insurers selling policies directly to individuals and families – the type of coverage in the ACA exchanges.

On average, the insurers “are on a path toward regaining profitability in 2017,” the study concluded.

“That could still all blow up through administration actions or what Congress might do,” said Larry Levitt, Kaiser’s senior vice president.

For the coming year, officials in several states have worried that they might have areas without any insurers willing to sell plans on their exchanges. About 25,000 customers in 38 counties in Ohio, Nevada and Indiana face that prospect at the moment.

Of the 20 million other people who rely on the ACA’s insurance benefits – through either marketplace plans or an expanded version of Medicaid – their presence is part of the buzz saw thwarting Senate Republicans’ efforts to demolish the law.

History is not on the Republicans’ side. Congress has never managed to reverse a major program of social benefits once constituents have begun to draw upon it. And it took eight decades of futile efforts by presidents from both parties before President Barack Obama and a Democratic Congress achieved a major expansion of health insurance aiming to encompass all Americans.

So even with the Republican domination of political Washington, the collapse of the Senate’s Better Care Reconciliation Act is more norm than outlier.

Still, it leaves consumers and insurers alike craving certainty.

The failure of the Senate bill “is a victory for consumers, but they are still on unstable ground until the administration shifts their approach and starts working not to tear down their health care,” said Frederick Isasi, executive director of Families USA, a liberal consumer health lobby.

Last week, as Senate Republicans were sparring over their bill, Cigna chief executive David Cordani said that what he most wanted from lawmakers was “clarity around the ruleset.” The ACA, he said, is a basket of many ingredients – the insurance requirement, the cost-sharing subsidies and the enrollment procedures among them.

“How that basket gets refreshed, changed or solidified,” he said, “is what’s most important.”