Protesters rally during House voting on the American Health Care Act on May 4.  (Yuri Gripas/Reuters)

The on-again, off-again threat from the White House to shatter the Affordable Care Act appeared to be on again Friday, as Politico reported that President Trump “told aides in a Tuesday Oval Office meeting that he wants to end” subsidies for people who buy health insurance on the state and federal exchanges.

The theory is audacious: Despite marking his fourth month in office, and despite the control his party holds over Congress, the plan from the president, party leaders and Republican campaign groups is to blame any increase on premiums on the Democrats. But so far, Republicans have stayed on message — and Democrats have struggled to draw attention to tremors in the insurance market that can be traced to the White House’s shaky management.

“It’s very clear that President Trump and Republicans here in Congress are not interested in improving the exchanges,” Sen. Chris Van Hollen (D-Md.) said at a news conference this week. “President Trump said, ‘The best thing, politically, is to let Obamacare explode.’ Here’s the thing: They’ve been doing the detonating from Day One.”

At issue are several vital components of the ACA, and the response of insurers to the White House’s on/off signaling. In his first week as president, Trump signed an executive order neutering the individual mandate, absolving the IRS from trying to collect a penalty from people who declined to buy insurance. The White House also briefly canceled advertising ahead of the ACA’s winter enrollment period — analysts argued that the decision cut down on new enrollees, even after the advertising started up again.

But the subsidies fight has always been seen by Republicans as a way to make the ACA unaffordable, thereby kick-starting the “death spiral” that the current funding system prevents. Out of power, Republicans sued to stop the subsidies, arguing that they were illegally paid out because Congress had not specifically appropriated the money that the Obama administration was distributing. Today, the subsidies could be stopped by that lawsuit’s success or by the president’s decision.

The wrinkle: Republicans are portraying any market failure not as a result of their management but as the basic ACA structure self-destructing. When the American Health Care Act was resurrected, House Speaker Paul D. Ryan (R-Wis.) led Republicans in citing the decision of Medica to pull out of Iowa’s exchange as proof of the ACA’s collapse.

“Iowa is down to one insurer,” Ryan said. “Now that one insurer is saying that it will have to pull out of 94 of 99 counties. This is happening right now! This is a crisis, and it is happening right now!”

In an interview with The Washington Post before the vote, Medica Vice President Geoff Bartsh cited the uncertainty over the government’s commitment to the ACA as “unknown risks” influencing the company’s decision. Yet since their push for repeal began in January, Republicans have talked about a “rescue” mission, portraying any market failures as inevitable. The urgency to pass the bill — which does not provide subsidies to people on the exchanges — is packaged as a response to the natural progress of the ACA.

“Whatever they do, they need to act, because more people are losing their health care, premiums are continuing to rise,” said House Majority Leader Kevin McCarthy (R-Calif.) in a Fox News interview this week, referring to the Senate.

Not for the first time, the two parties are engaged in political messaging that assume alternative realities. Democrats clutch to polling that has universally found voters ready to blame Trump and Republicans if the health-care system spins out of control. In a Kaiser poll released last month, three-quarters of all voters — including 51 percent of Republicans — said that the president and Congress should make sure the current law works. A majority of Democrats and independents said that any further problems would be the fault of Republicans.

Yet in that poll, just 34 percent of Republicans said that health insurance setbacks, such as higher premiums, would be the fault of Trump and Congress. Republican messaging plays not to the skeptics but to the base — and to a sense that Democrats would be hypocrites if they blamed anyone but themselves for a staggering ACA.

“Last year, Democrats blamed the insurance companies. Now, they’re blaming Republicans,” wrote Republican Nationial Committee rapid-response director Michael Ahrens in a Friday email to reporters. “Not surprisingly, no one is buying it.”

That messaging email, however, provided just three pieces of evidence. Two were CNN interviews in which Democrats were reminded that “insurers were leaving before Trump won.” One was a 2016 campaign clip of NBC reporting on higher premiums posing a risk for Democrats.