And one issue that was discussed: electability. It's a theme that's common in politics. And for Clinton, it's also been a campaign issue. Early in the campaign, Clinton raised the issue of Obama's lack of experience and how that could mean he wouldn't be electable in the general election. But that all came to an end Wednesday night when asked if Obama could win the general election, Clinton said emphatically that Obama could win against John McCain.

Political observers say Clinton's public comment about Obama being electable could cut into her ability to raise money in the states ahead. And a lack of money means less of her message will get out, helping Obama.

But Obama is having problems of his own, as he works to explain a comment that has put him into trouble in the past week. During Wednesday night's debate in Pennsylvania, Obama acknowledged that some voters may have been offended by a recent remark made in front of wealthy donors during a private fundraiser.

"Well I think there's no doubt that I can see how people were offended. It's not the first time that I've made a statement that was mangled up. It's not going to be the last" Obama stated in his defense.

"You go into some of these small towns in Pennsylvania, and like a lot of small towns in the Midwest, the jobs have been gone now for 25 years and nothing's replaced them... And it's not surprising then they get bitter, they cling to guns or religion..." was the remark made by Obama a week ago causing the controversy.

And in Wednesday night's debate, Obama went further in trying to put his controversial comment in context. He says the comment was more about the us economy than any group of people.

"They end up focusing on those things that are constant like religion. They end up feeling this is a place where I can find some refuge. This is something I can count on. They end up being much more concerned about votes around things like guns, where traditions have been passed on from generation to generation " Obama added.

Wednesday night's debate in Philadelphia was the 21st debate of the Democratic presidential nomination battle. The Pennsylvania primary is this upcoming Tuesday. The campaigns are talking about one more debate prior to the May 6th primaries in North Carolina and Indiana.

As the Democratic candidates work toward one nominee and this summer's convention, Republican John McCain is raising money and campaigning in states that will be important to him in the general election. One talking point of interest this week: the government's response in helping the nation's economy.

McCain says immediate action on the economy could include elimination of federal gasoline and diesel taxes for the summer driving season.

"I think there's some immediate actions we can take and one of them is a summer gas holiday. Wouldn't it be nice if the next time that you went to fill up your gas tank that 18 cents a gallon less you'd pay at the gas pump? I just think it might be nice for Americans who will be traveling this summer to be able to have a holiday from the gas taxes that they pay" said McCain.

As McCain takes a question from a college student about what he thought of Clinton's drinking a shot of whiskey in a bar last weekend.

"Whatever makes Senator Clinton happy is..." laughed McCain.