After the past couple weeks or so, it's obvious Clinton is just doing laps around Obama.
Obama, the poor guy, just doesn't know what he's doing. And I don't know if it's a ploy by Hillary to Just look more mature than the Illinois Senator, but it apparently isn't hard at all.
In the CNN Youtube debate, when the Democratic candidates were asked if they would get together with dictators (Kim Jong, Fidel, etc.) within the first year, Obama said of course. He also said it was a "disgrace" that it wasn't happening now. (I think it's rather amusing that he'd be so eager to speak with these people while backing out of a Fox News debate) Clinton came back to say she wouldn't be so quick to meet, she said it would be completely based on the context of the situation and whether her meeting might be used as propaganda for the countries involved.
Similarly, when asked about using nuclear weapons, Obama said that he would never use them, and then amended the statement, saying he would never use them when civilians were involved. Hillary Clinton chastized Obama, saying that past presidents and powers have used nuclear threats to maintain peace, and it would be unwise to just come out and say that you would never use them.
Now, as I said, I'm not sure if these responses are just to make Hillary look more mature than the Obama the lightweight, but it's working.