President Joe Biden asked Congress to pass a nationwide ban on AR-15s and similar firearms during his annual state of the union speech.

The president urged federal lawmakers to restrict the sale of the popular firearms as he laid out his policy agenda for the year ahead. He cited recent mass shootings in California as motivation to “do something” on guns. He touted the bipartisan gun law passed in the wake of the Uvalde elementary school shooting but insisted further gun restrictions were necessary to solve the problem.

“Ban assault weapons now! Ban them now,” Biden said. “Once and for all.”

The call represents a doubling down on one of the president’s marque gun policy proposals, which he claims will prevent future mass shootings. However, it comes as support for such a ban has fallen in recent months. Just the day before the president’s speech an ABC News/Washington Post poll found a majority of Americans now oppose banning assault weapons.

Still, President Biden said he could get a ban passed.

“We did it before,” he said. “I led the fight to ban them in 1994.”

Public opposition is only one of the hurdles that have expanded lately. Assault weapons bans are on increasingly shaky legal ground following last year’s Supreme Court ruling in New York State Rifle and Pistol Association v. Bruen. The High Court followed up that ruling by vacating a lower court decision upholding Maryland’s assault weapons ban and remanding it back down for new proceedings. Two federal judges have blocked assault weapon bans implemented by localities in Colorado, and state judges have blocked the ban Illinois passed last year.

Assault weapons bans have enjoyed a resurgence in some sectors, though. Last year, Democrats passed the first ban through the House of Representatives since 1994. The new Illinois ban followed closely after one in Delaware to become the first statewide bans since 2000. Members of the president’s party are also strongly considering ban proposals in Washington, Rhode Island, Colorado, and New Mexico this year.

The president said Congress should send a ban to his desk as soon as possible–something unlikely to happen given current Republican control of the House.

“Let’s finish the job and ban assault weapons again,” the president said.