Kerrying it far enough
"I have no intention whatsoever of apologizing for my remarks. I think the Republicans need to start talking about the real issues before the country," Kerry said.
Kerry actually does go on to clarify his comment by citing examples of Republican smear tactics against McCain and Cleland. But by leading with a "no apologies" stance there is hope that he can appear tough without appearing loonie. In a way, the "I was right and here are some examples of how I was right" approach fulfills the need to clarify without appearing to backtrack.
I still think it would have been better for Kerry not to have made the comment in the first place and I hope his criticism in the future is more focused. But this is a positive sign that he can recover from stumbles when they happen.