As the shutdown’s toll becomes clearer, the president aims to keep his pledge – but Democrats have reason to resist

There are two chants that everyone remembers from Donald Trump’s campaign rallies. One is “Lock her up!”, aimed at Hillary Clinton, a demand not likely to be met unless America becomes a banana republic. The other is “build that wall!”

It is now crunch time for this central, defining promise of the Trump candidacy and “make America great again” movement. The US president says he will not support a bill to fully fund the government until he secures $5.6bn for a wall on the US-Mexico border.