House Democrats[1] have pledged to use their new majority to pass gun control legislation, with a bill to expand background checks on gun purchases named as one of their top legislative priorities next year.

But the Republican-controlled Senate is likely to block even moderate, bipartisan gun control measures from becoming law.

It’s “highly unlikely there will be restrictions passed”, Senate majority leader Mitch McConnell said on Friday, according to Bloomberg News[2], when he was asked if the Senate would take any action after another mass shooting. The attack at a country music bar in California on Wednesday left a dozen people dead.

Congress has not passed any substantial federal gun control legislation in nearly 25 years, even as researchers say high-profile mass shootings appear to be growing more frequent.

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A bipartisan bill to expand background checks, co-sponsored by Democrat Mike Thompson of California and Republican Peter King of New York, was likely to pass in the House, Drew Hammill, the current House minority leader’s deputy chief of staff, told the Guardian.

Even passing gun control legislation in just the lower chamber of Congress would represent major progress. Just two years ago, after a mass shooting at a nightclub in Orlando left 49 people dead, House Republican leaders refused even to allow a vote on gun control legislation, prompting Democrats to lead a 26-hour sit-in [3]on the floor of the House.

Polls show that overwhelming majorities[4] of Americans – Republicans, Democrats and gun owners of both parties – support expanded background checks on gun sales, as well as laws to prevent people with mental illnesses from buying

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