When President Trump agreed to reopen the government for three weeks to negotiate a border security deal, he left open the possibility of another government shutdown.

On Sunday, Mick Mulvaney, Trump’s acting chief of staff, said the president isn’t bluffing. “He is willing to do whatever it takes to secure the border,” Mulvaney said on CBS’s “Face the Nation.” “He does take this very seriously.”

Is that a real risk or just an empty threat to drive congressional negotiators to act? Here’s the case for either.

The government shuts down again.

The lawmakers assigned to the conference committee have the unenviable task of figuring out how to address border security and other immigration policies in a way that will appease both the White House and Democrats, who control the House. Three weeks is not nearly enough time to come up with a deal on a subject that has evaded Congress for decades.

Even Trump is dubious that Congress can pull together a deal he’d accept. In an interview with the Wall Street Journal, he put the odds at less than 50-50. He also said he probably won’t accept anything less than $5.7 billion for a physical barrier at the border. And he reaffirmed that another government shutdown is “certainly an option.”

The appeal of a shutdown makes sense for Trump. The president faced a lot of criticism from his base for blinking first on the shutdown. The same people who persuaded him to hold firm and allow the government to partially close are now furious that he relented. In turn, he’s furious about the narrative that emerged from the shutdown that Democrats were victorious and that he lost badly. A shutdown would be unproductive, but it’s not out of the question that Trump does it again to save face with his base. But then the question becomes, to what end?

No way will there be another shutdown.

Republicans emerged from the longest shutdown in American history bruised and battered. By its final days, it was clear their resolve was shaken and Trump couldn’t depend on their defending the shutdown in the name of border security for much longer. Now that the House and the Senate reopened the government by unanimous consent — meaning no one objected — it will be almost impossible for Republicans to say that they can’t fund the government without border wall money come the Feb. 15 deadline. Even if Trump didn’t learn from the last one and refuses to sign another continuing resolution, Congress might well have enough votes to override his veto to keep the government funded.

So what will happen in this scenario? There are three possibilities. Here they are, ranked from least to most likely.

  • Congress makes a deal: In this most unlikely of circumstances, the 17 lawmakers chosen to write a border security compromise actually come up with a plan that everyone can agree to. In that universe, the Democrats would have to agree to some kind of physical barrier at the border or Trump would have to agree to go without. Perhaps he could make the case that enhanced technology is some kind of virtual barrier, and that’s what he meant all along? A deal would also likely have to address the issue of “dreamers,” the undocumented immigrants brought here as children whose protections from deportation under President Barack Obama were overturned by Trump. It’s hard to imagine Democrats accepting anything less than permanent protections and a path to citizenship for DACA recipients. 
  • Congress keeps funding every agency but the Department of Homeland Security: The immigration battle is playing out within the spending bill for DHS. Democrats have suggested several times that unrelated agencies, such as Treasury and the Justice Department, be funded and the border debate be carried out within the confines of funding Homeland Security. The problem there would be the Transportation Security Administration (TSA) is under DHS’s jurisdiction, as are the Coast Guard, Border Patrol and Secret Service. 
  • Congress doesn’t reach a deal and Trump declares a national emergency: This seems like the most likely occurrence given the state of things in Washington. It’s a door Trump has left open, one that would allow him to satisfy his base while also avoiding a shutdown. If Trump did declare the situation at the border a “national emergency,” and tried to divert funds to building his wall, there would certainly be a lawsuit. It will be difficult for Trump to argue that there actually is an “emergency” forcing him to work around Congress given he’s willing to wait weeks for Congress to act. This is a scenario, though, in which both sides win. The Democrats stand their ground against the wall. Trump blames their inaction and declares an emergency. And if the courts strike it down, Trump tweets angrily about the system, but all the talk about a wall fades away.