Senator fields questions from MSNBC's Matthews, packed arena of Villanova University students.
Hits many familiar themes, including national security, climate change, spending.
--Says it would be "difficult" to put Tom Ridge on his ticket due to his support for abortion rights. "The respect and cherishing of the right of the unborn" is a "deeply held belief of mine."
--Keeps up pressure on Obama over accepting public campaign funds.
--States that Obama is not elitist, but his comments were:
"The fact that (Americans) like to hunt has nothing to do with their economic condition... Their faith is something that goes on in bad times and in good."
