Almost everyone seems to agree that Donald Trump’s threat to close the southern border, one he seemingly made on impulse over the weekend, would be catastrophic. “I understand the president’s frustration, but the unintended consequences of that would be bad for everybody: economic, diplomatic,” Texas senator John Cornyn told Politico Monday night, a sentiment common among Republican lawmakers who have questioned whether Trump understands the full implications of his proposal. In public, Trump’s aides have testified as to his resolve: the threat, Kellyanne Conway told Fox News over the weekend, “certainly isn’t a bluff.” But behind the scenes, the White House has reportedly launched a campaign to distract Trump, in the hopes he’ll drop the idea altogether.

As Politico reported Tuesday, aides have spent the past several days on a “panicked” effort to put together a stricter immigration proposal to send to Congress—ideally, one that would distract Trump from his border-closure plan, heading off “another self-inflicted wound.” (Such a plan is unlikely to make it through the Democratically controlled House, but hey, desperate times.) Notably, per Politico, “there was discussion all day Monday” of bringing Department of Homeland Security Secretary Kirstjen Nielsen back from London, where she’d landed to take several meetings. Less than 24 hours after she’d left D.C., she was back—a sure sign of a White House in crisis mode.

According to CNN, administration officials “have been unable to articulate when or for how long the president would close the border, whether that closure would apply to air travel and what it would mean for the U.S. economy.” Kevin Hassett, one of Trump’s top economic advisers, has said it’s something he’ll surely be looking into. Senior policy adviser Stephen Miller, meanwhile, reportedly wants to use the crisis to force Congress to consider new laws restricting asylum seekers, “so they could then shift the blame for recent record-breaking immigration numbers to lawmakers.”

Trump has insisted that closing the southern border would “stop the many thousands of people trying to get into the USA,” a necessary evil, he insists, while the nation waits for its shiny new border wall. But experts say it would do little to actually stem the flow of undocumented immigrants and refugees, with the happy side effect of devastating the U.S. economy. Several experts told CBS News that shutting down the border would cost both the U.S. and Mexico up to a billion dollars a day, forcing prices up due to near-immediate shortages of imported goods and parts. The auto industry would shutter within a week, avocados and berries would disappear from grocery store shelves a few weeks later, and millions of workers who cross the border legally would lose access to their jobs or school. “It’s an economic impossibility. Literally, the two economies would grind to a halt,”Duncan Wood, the director of the Wilson Center’s Mexico Institute, told CBS MoneyWatch. “Both economies are set up to depend upon cross-border trade.”

In theory, the threat of economic devastation would be enough to give the president second thoughts—that is, if he were seriously considering closing the border in the first place. Conway may hold that Trump isn’t bluffing. But acting White House chief of staff Mick Mulvaney’s Sunday interview tells a different story. Appearing on ABC News’s This Week, Mulvaney blamed Democrats for forcing Trump’s hand on the issue, appearing to dangle the prospect of economic collapse as an incentive for lawmakers to give the president what he wants. “We need border security, and we’re going to do the best we can with what we have,” Mulvaney said. “If closing the ports of entry means that, that’s exactly what he intends to do.” On Tuesday, White House press secretary Sarah Huckabee Sanders told reporters, “This isn’t our first choice.”