Kerry claimed today to a union in Boston that Swift Boat Veterans for Truth was "a front for the Bush campaign. And the fact that the president won't denounce what they're up to tells you everything you need to know: He wants them to do his dirty work."

McClellan noted: "We will never raise questions about his service. We haven't, and we won't."

He added: "Sen. Kerry knows that his latest attack is false and baseless. The president has condemned all of the ads by the shadowy groups. We have called on Senator Kerry to join us in calling for an end to all the unregulated soft money activity that is going on in this campaign."

Time to put up or shut up, Senator. Are the likes of George Soros and Stephen Bing too filthy rich to shun?

Editor's note: