First he was against gun control now Pennsylvania Senator Bob Casey has had a change of heart.

He says the Connecticut school shooting is what flipped the switch for him.

Casey says the shooting in Newtown last week moved him deeply in a way that wasn't the case before and that is part of why he is changing his position.

Casey has long been a pro-gun Democrat, often calling guns in Pennsylvania "a family tradition."

But after 20 children and six adults were gunned down at Sandy Hook Elementary School, Casey says he changed his opposition to gun control.

"The idea that we can do nothing about that I think doesn't make sense and that is why I have changed my position on those two measures," said Casey.

Casey wants to ban assault weapons and high capacity ammunition clips.

A task force led by Vice President Joe Biden will look at the issue of gun control and ways to prevent more mass shootings.

"There is no reason why someone who is hunting or even someone who is protecting themselves needs 30 bullets to do that and unfortunately in this case you had a very evil person with a high powered, military-style rifle," said Casey.

Casey says the federal government needs to also focus on mental health issues.

In 2007, The  National Rifle Association backed a proposal to include mental health records in background checks after 32 people were killed at Virginia Tech.

Pennsylvania's other Senator, Republican Pat Toomey, says he too would consider legislation.

"Among other things, we need to implement more effective methods of identifying and protecting ourselves from dangerous and deranged individuals who seek to carry out such atrocities," said Toomey.

Casey says treatment is just as important as screening.

"We know that good treatment works. That we can provide medication to them to heal them to make them healthy again with regard to mental  health," said Casey.

Casey's critics say he is a political opportunist using this tragedy to make himself look good.

Casey says the understands the criticism but that is not the case.