Washington ? Senate Republicans scuttled their election-year gun legislation Tuesday after Democrats succeeded in winning approval of amendments to extend an assault weapons ban and require background checks on all buyers at private gun shows.

The 90-8 vote against the bill handed Democrats and gun-control advocates an unexpected victory in the GOP-controlled Congress. It all but eliminated any chance for gun legislation this year.

“Twenty-four hours ago, I knew of no one who would have said we would be sitting where we are right now,” said Mike Barnes, president of the Brady Campaign gun-control group. “The NRA’s highest legislative priority was just defeated.”

Beginning in September, the gun industry can resume making, importing and selling military-style semiautomatic weapons that were outlawed a decade ago. Nonetheless, Democrats say they now have the Senate on record as supporting the assault weapons ban by a 52-47 vote even though Republican leaders have vowed they won’t allow the House to consider it this year.

“Now we know we have our vote, and we will come back,” said Sen. Dianne Feinstein, D-Calif. “If we can’t get it done by Sept. 13, then you can be sure it’s going to be in the presidential campaign as a bona fide issue as to whether the American people want AK47s, street sweepers and Uzis sold once again.”

The National Rifle Assn., a political juggernaut because of its 4 million members, e-mailed senators in both parties just before the final roll call urging them to vote against the bill after Democrats succeeded in adding the gun-control measures to the GOP-written legislation.

“While we will continue to work to save the U.S. firearms industry, we have said from the start that we would not allow this bill to become a vehicle for added restrictions on the law-abiding people of America,” NRA Vice President Wayne LaPierre Jr. wrote.

Republican senators said they might attempt to revive the gunmaker-immunity bill. “We will see if we have enough time to get it out this year,” said Sen. Larry Craig, R-Idaho, the bill’s sponsor who was forced to vote against his own legislation because of the amendments.