Yet however this ends, Mr Trump may feel the wall is as useful as ever. His remarks in 2016 made it clear that it was as much about tactics as his strategy of fostering fear and division. It is to be invoked in times of need. Those have arrived. Mr Trump looks increasingly anxious for a deal in the trade war he started with China. Above all, Robert Mueller’s investigation moves closer and looms larger. On the same day that the president spoke, we learned that Mr Mueller has accused his former campaign chairman, Paul Manafort, of sharing polling data with a Russian man linked to Moscow’s intelligence agencies. Is it any surprise that Mr Trump would rather discuss the border? The wall does not have to be real to be useful: the only question is whether its magic is gradually wearing off.