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