Bernie Sanders, a favorite of grass-roots liberals despite his mixed record on gun control, joined his Senate colleagues Thursday in calling for a crackdown on firearms a day after the mass shooting in San Bernardino.

Standing alongside California’s two Democratic senators, Barbara Boxer and Dianne Feinstein, at a Capitol Hill news conference, Sanders said the steps he supports include expanded background checks and efforts to keep firearms out of the hands of people who commit domestic violence.

“Let me paraphrase what President Obama said recently. And what he said is this is not an easy problem to solve. But just because it is not an easy problem to solve does not mean that we should not do everything that we can,” the Vermont senator said. “Now, the bad news is that this nation is divided over gun legislation.”

Sanders’ comments were similar to statements he has made throughout his bid for the Democratic presidential nomination, where he faces a two rivals, Hillary Clinton and Martin O’Malley, with a history of backing tougher gun controls.

In 2005, for instance, Sanders supported legislation protecting gun manufacturers and sellers from lawsuits seeking to hold them liable when firearms end up in criminal hands.

“That was a terrible mistake," Clinton said in last month’s Democratic debate. “It basically gave the gun lobby even more power to intimidate legislators, not just in Washington but across the country.”

In response, Sanders said there were elements of the bill he supported but repeatedly demurred when asked if his vote had been a mistake.

O’Malley suggested Thursday that the shootings at a San Bernardino center for the developmentally disabled could be a lead to change in the fractious gun control debate.

"'We’ve now had more mass shootings than we’ve had days in this year, and perhaps this is the incident that tips the balance and we finally do this,” O’Malley said in an interview on the Fusion television network.

Efforts to pass tougher federal gun laws have stalled because of deep partisan polarization, even after repeated mass shootings, including incidents in 2012 at an Aurora, Colo., movie theater and at Sandy Hook Elementary School in Newtown, Conn.

In general, Democrats have called for stiffer gun laws while Republicans have said a crackdown on firearms would infringe on the 2nd Amendment rights of gun owners.

For her part, Clinton said Thursday that tougher gun control is needed.

"We need to take action now," she said in a note to supporters on Twitter.