Senate Majority Leader Harry Reid (D-Nev.) said the struggle for tougher gun legislation was not over.
"This is not the end of the fight. Republicans are in an unsustainable position," he said, after tougher requirements on background checks for gun purchasers were defeated. Reid offered no timetable for renewing the drive to enact legislation that President Barack Obama has placed near the top of his domestic agenda.
Another Democrat, Sen. Joe Manchin of West Virginia, said the proposed expansion of background checks that he co-authored would have passed easily had it not been for the National Rifle Association's decision to take the vote into account in deciding which candidates to support or oppose in 2014.
"If they hadn't scored it, we'd have had 70 votes," he said. Instead, it drew 54, six short of the 60 needed to advance.
The fate of the bill was sealed in a string of votes on Wednesday, when Republicans, backed by a small group of rural-state Democrats, rejected more extensive background checks for gun purchasers and also torpedoed proposed bans on assault weapons and high-capacity ammunition magazines.
The Senate delivered its verdict four months after a shooting at an elementary school in Newtown, Conn., left 20 first-graders and six educators dead. The tragedy prompted Obama to champion an issue that Democrats had largely avoided for two decades, and that he himself ignored during his first term in the White House.
Though the gun control bill was moribund for the foreseeable future, the Senate approved two minor amendments Thursday. One by Sen. John Barrasso (R-Wyo.), which would cut aid to state and local governments that release information on gun owners, passed 67-30. Another, by Sens. Tom Harkin (D-Iowa) and Lamar Alexander (R-Tenn.) bolstering federal mental health programs, passed 95-2.
A leading gun control opponent accused Obama of taking the "low road" when he harshly criticized lawmakers who voted against key provisions.
"When good and honest people have honest differences of opinion about what policies the country should pursue about gun rights . . . the president of the United States should not accuse them of having no coherent arguments or of caving to the pressure," said Sen. John Cornyn (R-Texas.).
Obama spoke in angry tones at the White House on Wednesday after the Senate scuttled the legislation, calling it "a shameful day for Washington," and vowed to continue the fight.