Not so crazy, but I don't think so, because the Nixon White House went all out to sink Kerry in his Jane-Fonda-Tom-Hayden Days.
However, here's another possible gambit: When Clinton was taking heat for the mysterious as-yet-unexplained years he spent wandering around Russia, East Germany, and Czechoslovakia after he left Oxford under the cloud of a possible rape charge etc, his wonkstaff tried to float the idea that HE was actually a loyal patriot working under cover. No one bought it and they dropped it. Kerry's folks may now be trying the same thing.
Look for Tom Woodward to take up this cudgel. Kerry may well have been a government agent, but I don't think it was for our team. Some day, we'll get the REAL (if indeed there is such a thing a s a "real" KGB File) KGB files on Clinton and Kerry (not to mention Lee Harvey Oswald)... and the Holbrooke fink ...who also spent a lot of time behind the Iron Curtain in his youth.
"Kerry may well have been a government agent, but I don't think it was for our team."
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Agreed!