Is President Trump trying to strengthen or to dismantle Obamacare?

Though Trump has long vowed to repeal the health care law, he and his administration vacillate between stabilizing the individual market and undermining it.

These mixed messages -- which were on display this week -- are not sitting well with health insurers, who must decide soon whether to participate in the exchanges in 2018. Already, some have pulled out and others have said they are evaluating their involvement.

Trump threatened to upend Obamacare in an interview with the Wall Street Journal on Wednesday. He said he hadn't decided whether to continue funding cost-sharing subsidies that reduce deductibles and out-of-pocket costs for low-income consumers. Without these payments, insurers will almost certainly exit the exchanges.

"Obamacare is dead next month if it doesn't get that money," Trump told the newspaper. "I haven't made my viewpoint clear yet."

Related: Trump's mixed messages on Obamacare subsidies could prompt insurers to flee

But the next day, his administration finalized a new rule aimed at stabilizing Obamacare. The measures address many complaints insurers had about the exchanges, but will make it tougher for consumers to enroll.

The rule shortens the open enrollment period to six weeks -- from November 1 to December 15 -- rather than three months. It also makes it harder for people to sign-up outside of this period, requiring enrollees to provide documentation to prove they are eligible because they lost a job, had a baby, got divorced or had another life change. And it requires consumers to pay any past-due premiums they owe before enrolling again with the same insurer.

The measure also allows insurers to raise deductibles and co-pays. While this could lower premiums for some, it would increase enrollees' out-of-pocket costs. And it eliminates federal oversight aimed at making sure there are enough doctors and hospitals in every insurance plan's network.

"While these steps will help stabilize the individual and small group markets, they are not a long-term cure for the problems that the Affordable Care Act has created in our health care system," said Seema Verma, administrator of the Centers for Medicare & Medicaid Services, which runs Obamacare.

Related: More than half of Americans approve of Obamacare now, Gallup poll finds

While insurers were happy with the rule, they pressed the administration to guarantee funding for the cost-sharing subsidies.

"Health plans and the consumers they serve need to know that funding for cost-sharing reduction subsidies will continue uninterrupted," said Marilyn Tavenner, CEO of America's Health Insurance Plans, a main industry lobbying group. "Without funding, millions of Americans who buy their own plan will be harmed."

Consumer advocates, meanwhile, worry that the roadblocks set up by the new rule will actually hurt Obamacare by deterring healthy people from signing up.

"While the Administration claims the changes are needed to stabilize the insurance market, many of them would reduce market stability by shrinking enrollment and making the pool of people with coverage sicker, on average," said Sarah Lueck, senior policy analyst at the Center on Budget and Policy Priorities, a left-leaning group.