Washington woke up to a partial federal government shutdown early Saturday after lawmakers missed a midnight deadline to approve new funding. The lapse followed days of tense negotiations centered on money for the Department of Homeland Security.

Here’s the thing. Most of the government was set to keep operating under a short-term spending plan that cleared the Senate late Friday. That bill would have funded federal agencies through the next budget window while giving lawmakers two additional weeks to resolve disagreements over DHS. The House did not take it up in time.

What this really comes down to is immigration enforcement. Democratic lawmakers pushed to attach limits on certain DHS operations, citing recent incidents involving federal agents. Republicans rejected those conditions, arguing they would interfere with border security and law enforcement duties.

As a result, funding for DHS and several other agencies expired. Essential services remain active, but many federal employees now face furloughs or working without pay.

House members are expected back in Washington on Monday, raising the likelihood that the shutdown could be brief if a compromise is reached quickly.