WASHINGTON — Congress on Thursday adopted a stopgap spending measure to finance the government through Dec. 3 as lawmakers dashed for an earlier-than-expected exodus from Washington and headed home to focus on the midterm elections.

“We may not agree on much, but I think with rare exception all 100 senators want to get out of here and back to their states,” the Senate majority leader, Harry Reid of Nevada, said Wednesday afternoon. And by 8:30 p.m., most of them were on their way. A half-dozen senators left before the final vote on a motion to adjourn.

The last day of the brief September session was as notable for what did not get done as for what did. Neither chamber voted on the expiring Bush-era tax cuts as Democrats skipped a politically treacherous debate and Republicans slammed them for it.

In the Senate, the vote on the stopgap spending bill was 69 to 30, with 11 Republicans joining Democrats to approve it. Senator Russ Feingold, Democrat of Wisconsin, and 29 Republicans were opposed. Senator Lisa Murkowski, Republican of Alaska, who is mounting a write-in campaign to keep her job, was absent.