The most recent dust-up involves Wes Clark's comments over the weekend on Face the Nation (offending comments in bold).
CLARK: He has been a voice on the Senate Armed Services Committee. And he has traveled all over the world. But he hasn't held executive responsibility. That large squadron in the Navy that he commanded — that wasn't a wartime squadron. He hasn't been there and ordered the bombs to fall. He hasn't seen what it's like when diplomats come in and say, "I don't know whether we're going to be able to get this point through or not, do you want to take the risk, what about your reputation, how do we handle this publicly? He hasn't made those calls, Bob.Although Clark's comment was undisciplined and he should have known better, the context demonstrates that he was making a valid argument (i.e., that McCain's misfortune does not somehow mean that he is more qualified to lead the nation than Obama). You may agree or disagree with that argument, but the argument itself is not offensive.
SCHIEFFER: Can I just interrupt you? I have to say, Barack Obama hasn't had any of these experiences either, nor has he ridden in a fighter plane and gotten shot down.
CLARK: I don’t think getting in a fighter plane and getting shot down is a qualification to become president.
Let's move on.