PHILADELPHIA (AP) — Long opposed to new gun laws, Sen. Bob Casey said Wednesday that in the wake of the Connecticut school shootings he would now support bills to ban assault weapons and high-capacity ammunition clips.

Casey, D-Pa., told The Philadelphia Inquirer the shootings that left 20 students and six staff dead in Newtown, Conn., have “haunted” him. He won a second term last month while still touting his opposition to gun control, but he said he reassessed the gun issue over the weekend.

“The power of the weapon, the number of bullets that hit each child, that was so, to me, just so chilling it haunts me. It should haunt every public official,” Casey told the newspaper during an interview in Washington, D.C.

Casey spoke on the same day that President Barack Obama pressed lawmakers to reinstate the ban on military-style assault weapons and restrict high-capacity ammunition clips — the measures that Casey says he now supports.

“If those two bills come before the Senate, I’ll vote for both,” Casey said, adding that the change amounted to being “summoned by your conscience.”

His statements come as other Democratic politicians who have previously taken more pro-gun positions, including Senate Majority Leader Harry Reid and West Virginia Sen. Joe Manchin, have indicated an openness to tighten gun laws.

Casey said he still has “strong” support for the Second Amendment. But he expressed regret about not reassessing his position after the shootings that killed 12 at a movie theater in Aurora, Colo., earlier this year and after the Virginia Tech shootings in 2007.

“We’re all open to that charge and that’s a fair question. That should weigh on us as well, any public official in my position,” he said. “I wish that maybe I had spent more time thinking about those other tragedies in the way that I have on this.”

He said he knows that he will face criticism from gun rights supporters for his change, but said the two measures are important steps to take.

“There’s no question I’ll be open to criticism and I understand that,” Casey said. “I just believe that in light of what’s happened, in light of measures we can take to lessen the chances that will happen (again), that these are two steps we can take.”

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