WASHINGTON — Sen. Chris Murphy (D-Conn.) on Thursday reintroduced universal gun background checks legislation that is overwhelmingly popular with the American public — but not with a majority of U.S. senators.

Federal law requires criminal background checks for firearm sales only at licensed dealers. Private sales between individuals, including at gun shows or online, aren’t subject to background checks.

“This is one of those wild issues in which 90% of the American public have made up their mind and we still can’t move the proposal through the Senate,” Murphy told HuffPost. “This is the holy grail of gun policy: It’s wildly popular, and it makes a big difference.”

Federal law prohibits certain people from buying guns, including those who have been convicted of violent crimes or who are subject to restraining orders. But without a background check, there’s nothing to stop them from buying a gun. According to one estimate from 2017, nearly a quarter of new gun owners bought their weapons without a background check.

Sen. John Barrasso (R-Wyo.), a member of the Senate Republican leadership team, told HuffPost that he would “obviously” oppose a universal background checks bill and so would any senators who favor protecting Second Amendment rights. Not all Democrats will support Murphy’s bill, either; Sens. Joe Manchin (W.Va.), Kyrsten Sinema (Ariz.) and Jon Tester (Mont.) refused to co-sponsor last year’s version, and Manchin told HuffPost this week that his position hasn’t changed.

With Republicans in control of the House for at least the next two years, universal background checks will remain a non-starter.

But Congress has not been totally paralyzed on gun violence, which in recent years eclipsed car wrecks as the leading cause of death of children in the U.S. Last year, Murphy partnered with Republicans on a law that, among other things, expanded background checks for gun buyers between 18 and 21 years old. The FBI told HuffPost this week that the expanded checks had denied dozens of gun sales so far.

The 2022 law also modified the legal definition of who counts as “engaged in the business” of selling guns and therefore must register with the federal government as a firearms dealer. The new text stresses that someone’s a dealer if “the intent underlying the sale or disposition of firearms is predominantly one of obtaining pecuniary gain,” meaning profit.

Sen. John Cornyn (R-Texas), one of Murphy’s main Republican partners on last year’s bill, said that language change “basically did” what Murphy’s now trying to do with his universal background checks bill.

“If they’re in the business of selling firearms, they’re gonna be charged with a crime” if they don’t do background checks, Cornyn said.

The gun control group Giffords, which celebrated the new law, called the revision to the gun dealer language just a minor change: “The loophole that allows unlicensed sellers to sell guns without conducting background checks would remain open,” Giffords said on its website.