Obama Kicks Off Pennsylvania Tour

From CBS News' Maria Gavrilovic:

PITTSBURGH -- Barack Obama kicked off a six day tour of Pennsylvania today by nabbing his first major endorsement in the state. Sen. Bob Casey Jr, D-Pa., a superdelegate, announced his endorsement at a community gathering here. Obama said the endorsement came as somewhat of a surprise to him.

"I told him I'd love to have his support but I understood that we're behind in the Pennsylvania polls," Obama said.

"It would have been easy for Bob just to stay out of it, just to stay neutral. I think everybody would have accepted that."

Casey said he called Hillary Clinton last night to inform her of his decision and described her as being very "gracious." However, he said he was impressed by Obama's compassion, ideas, and by his ability to handle a tough campaign.

"He has appealed, as Abraham Lincoln asked us to do many years ago, to the better angels of our nature, and we appreciate that as he's campaigning," Casey said.

In his remarks, Obama disputed Clinton's argument on electablity. He said that her claim that she is more likely to beat John McCain in a general election is falsely based on longevity in Washington.

"Look if the contest between McCain and the Democratic nominee is who's been there longer, John McCain wins," Obama said.

"If the argument is who is going to pursue a foreign policy like George Bush's, then John McCain wins. If that's the criteria for being tough, if that's the criteria for answering the 3 o'clock phone call, that you voted for the war in Iraq, that you went along with George Bush's policies when it came to Iran and not talking to leaders that we don't like, then John McCain wins that fight."

The six-day bus tour is Obama's first major campaign push in the Pennsylvania, a state which Clinton argues is pivotal to securing the Democratic nomination. Casey will be campaigning with Obama for the full duration of the tour.