How do you define ‘wall’? Keeping Washington open may hinge on the answer.

Will the government shut down again in three weeks? That might depend on what the meaning of the word “wall” is.

Or rather, it might depend on whether Democratic and Republican congressional negotiators can agree on border security measures that meet their mutually exclusive “wall” definition needs.

Democrats are firmly opposed to a physical wall – “a big, beautiful wall,” in President Trump’s phrase. But they are open to spending for replacement fencing, levees, bollards, and electronic barriers. Mr. Trump has insisted on an imposing Great Wall-type structure, but at various times he’s said that would be concrete, or could be steel slats, or maybe even based on drones, sensors, and other “smart wall” technology.

Upcoming talks thus may be as much about semantics as about stuff. In this they could be a symbol for American politics in a polarized age, where the fight is about messaging as much as policy, and winning means the team on the other side of the aisle should lose.

The upshot: The “wall” has become what political scientists call a condensation symbol, something that stands for schism, frustration, fear of immigrants, Trump himself, opposition to Speaker Nancy Pelosi, and a lengthening list of other positions and feelings.

“All of these things are embodied by the wall itself ... all of this cultural symbolizing is packed into the wall,” says Jennifer Mercieca, an assistant professor and historian of American political discourse at Texas A&M University.

The 17 House and Senate negotiators named to come up with an agreement on Department of Homeland Security spending for fiscal year 2019 will meet for the first time on Wednesday. They have until Feb. 15 to strike a deal on border security that threads a needle and satisfies lawmakers of both parties on the wall and other difficult immigration issues.

The chairman and ranking minority member of the appropriations panels of both chambers will lead this conference committee. That’s cause for hope, say some analysts. Appropriators are generally pragmatic dealmakers used to simply finding an acceptable compromise between spending proposals. 

They could take Trump’s $5.7 billion wall request, find a midpoint with the Democrat’s $1.6 billion offer for non-wall security, and then finesse language that allows the president to claim he’s got a wall down payment, while Democrats insist that the money is for items that don’t really constitute Trump’s cherished hard barrier.

“It is possible for them to reach a basic agreement,” says G. William Hoagland, a senior vice president at the Bipartisan Policy Center in Washington.

The wild card, as has often been the case in the last two years, is the president. The wall was a core promise in Trump’s campaign but most congressional Republicans have shown only tepid interest in the concept, at best.

Thus a deal that satisfies the Senate GOP might not work in the Oval Office. In an interview published in The Wall Street Journal over the weekend, Trump said there was less than a 50-50 chance that Congress would strike an acceptable agreement. If it doesn’t include a “very strong form of physical barrier,” said Trump, he could invoke a national emergency and proceed on the wall by himself.

Such a declaration could quickly become mired in the courts. GOP lawmakers are worried it might eventually produce a precedent that future Democratic presidents could invoke to take executive action on their own big issues, such as climate change or health care.

But the president has also occasionally talked about the wall in a way that seems open to compromise with Democratic positions. He’s talked often about “steel slats” as an alternative to concrete slabs, and mused on occasion about the possibility the wall could include “smart wall” sections of drones and other non-permanent infrastructure.

It’s possible the president is sending up trial balloons with this sort of language, says David Barker, executive director of the Center for Congressional and Presidential Studies at American University. If he doesn’t think he’ll lose the right wing or his core supporters, he might edge closer to approval of a House-Senate compromise where he gets more border money, but there is language circumscribing the money’s use.

“That offers the possibility that Trump could claim victory because he got his underlying interests served, because he can say he secured the border, and Democrats can say they didn’t capitulate to this idea of the wall,” says Professor Barker.

After all, in a polarized world where voters pay less attention to detail and focus instead on cues given by party leaders, a “victory” can be in the eye of the beholder. The ability to present events in the best light has been a Trump trademark, and he could do that again if conferees produce a deal.

“Whatever he signs, he’s going to say it’s a win. It could be a bridge letting people in and he’d frame it as a win,” says Erin O’Brien, an associate professor of political science at the University of Massachusetts at Boston.

The “wall” lends itself to that kind of redefinition, because as noted above, it’s symbol as much as steel. Maybe – probably – more so.

Defining it as a condensation symbol, in which it includes meaning that is not directly relevant to the wall itself, is one way to look at it, according to Professor Mercieca of Texas A&M. It could also be seen as the opposite – an empty signifier. It means nothing, and everything, at the same time.

“So you can put whatever you want into it,” she says. “Discourse defines the ‘wall.’ ”