Right now, it's difficult to foresee anything that might force one side to budge to resolve the ongoing partial government shutdown, but one possibility is the looming threat of airport chaos.

With too many Transportation Security Agency workers calling in sick during a government shutdown in which they are being asked to work without pay, Miami International Airport has been forced to close one terminal early for the next three days. This comes on top of planned shutdowns of security checkpoints in airports across the U.S.

For now, the problem has been manageable and thus far has not let to widespread problems for travelers. But if the partial shutdown continues, the problem could deteriorate significantly.

To this point, there haven't been many incentives for either party to make a concession in the government shutdown fight. President Trump promised his voters a wall, and he's worried about caving in. Republicans are afraid to defy him and, by extension, the base of their party. Democrats, meanwhile, have no interest in funding a border wall, especially given that their voters are demanding total resistance to Trump.

At the same time that the parties have had relatively little reason to deal, the costs of the ongoing shutdown have been relatively small. Previous spending bills and the automatic nature of entitlement programs have meant that 95 percent of the federal budget is funded, lowering the pressure to make concessions.

Were there to be widespread reports of flight delays and huge airport security lines, however, that could change. Airplane travelers tend to be disproportionately businesspeople and upper middle class Americans; members of the media or friends or family of journalists; people who are politically active and more likely to have connections to lawmakers. It's easy to see how media could turn tweets about endless security lines and disrupted travel plans into a national crisis that hits politicians where it hurts.

Put another way, right now, there's a relatively low cost to not cutting a deal. Chaotic airport travel would change that dynamic and increase the cost of doing nothing. That could be the trigger that brings about some sort of end to the shutdown.