Why might the US government shut down? The Republicans control both chambers of Congress, but in the Senate - or upper chamber - they are short of the 60 votes they need to pass a spending bill. But Trump has dampened expectations of a deal, telling the BBC's US partner CBS News: "I just don't know how we're going to solve this issue." On the Republican side, Trump administration officials have been unwilling, so far, to offer any substantive concessions. Not all of government will shut down if Congress doesn't pass a spending bill.