WASHINGTON — The House voted overwhelmingly on Thursday to finance the government through late April, but a snag over the measure in the Senate threatens a shutdown of operations this weekend.

With Congress on the cusp of wrapping up its lame-duck session, Senate Democrats picked fights on behalf of two constituencies to whom President-elect Donald J. Trump appealed during his campaign — coal miners and steel workers.

The stopgap spending measure must be approved by the Senate by midnight Friday to keep the government open. But Democrats in the Senate, led by Joe Manchin III of West Virginia and Sherrod Brown of Ohio, are objecting because they want a better deal for thousands of retired coal miners who are set to lose their health benefits at the end of the year.

The spending bill extends the miners’ health coverage for only four months, which the Democrats view as insufficient.