1. It’s a showdown over President Trump’s wall.

The federal government shut down early Saturday after congressional and White House officials could not reach a compromise on a spending bill. The shutdown will continue for the next several days. The White House has indicated that Mr. Trump is sticking to his demand for $5 billion for a border wall. And Senator Mitch McConnell, the majority leader, adjourned the Senate until Thursday.

The shutdown has stopped work at nine federal departments and several other agencies. About 380,000 government employees will not be paid, and 420,000 others considered too essential to be furloughed are being forced to work without pay. (Workers have been reimbursed after past shutdowns.) Here’s a look at how the impasse is affecting federal departments.

The shutdown was part of a chaotic series of events in Washington this week, a fitting end for the 115th Congress and a fractious, emotionally charged year.