WASHINGTON — Senate Democrats fell one vote short Wednesday in a bid to overturn the Trump administration’s expansion of short-term health insurance plans that do not have to cover preexisting conditions and certain kinds of health care that the Affordable Care Act requires.
By forcing a vote on what they term ‘‘junk’’ plans, however, Democrats managed to put a spotlight on a key issue they argue will cut their way in next month’s midterm elections, where control of both the House and the Senate is in play.
Senator Susan Collins, Republican of Maine, joined with Democrats in supporting the resolution, which was opposed by the chamber’s other 50 Republicans.
To succeed, Democrats needed to lure the votes of at least two Republican senators in a chamber where the GOP has a 51-to-49 majority.
The resolution — spearheaded by Senator Tammy Baldwin, Democrat of Wisconsin — was brought to the floor after obtaining far more than the 30 signatures required to bypass the committee process and force a full Senate vote.
The resolution sought to overturn an administration rule finalized in August that Republicans argue offers cheaper alternatives to consumers interested in less-comprehensive health plans than those mandated by Barack Obama’s signature 2010 health care law.
On Tuesday night, President Trump issued the first veto threat, making clear he would veto the Democratic measure if it reached his desk.
‘‘These plans are cheap for a reason,’’ Baldwin said in a floor speech before the vote. ‘‘They do not have to provide essential health benefits like hospitalization, prescription drugs, and maternity care.’’
Baldwin pointed to one plan sold in her state that she said does not cover hospital care on a Friday or Saturday.
‘‘So, it will just be your bad luck if you happen to get sick and need health care on the weekend,’’ she said.
Baldwin also said that requiring coverage of preexisting conditions is personal for her. She relayed that when she was 9, she fell seriously ill and was hospitalized for three months.
‘‘I eventually recovered,’’ she said. ‘‘But when it came to health insurance, it was like I had some sort of scarlet letter. My grandparents, who raised me, couldn’t find a policy at any price that would cover me . . . All because I was a child who had been branded with those words: ‘preexisting condition.’ ”