[Sabertooth]

Considering that Kerry's group ended up plotting the assasination of United States Senators, I think the FBI interest in them was quite justified.

The FBI wasn't tailing the VVAW for the assassination plot, they never learned of it. Notice the citation from the FBI files that the Kerry campaign is putting forth as exculpatory (it's actually damning, as I'll explain):

""A review of the subject's file reveals nothing whatsoever to link the subject with any violent type activity," concludes a May 1972 FBI memo about Kerry provided by his campaign.

The FBI never learned of Kerry's presence at the VVAW's Phoenix Project discussions about assassinating six U.S. Senators, because the meeting in Kansas City was moved twice to avoid surveillance.

The reason this cite from the memo is actually trouble for Kerry is that it demonstrates he never informed law enforcement of the plot.

[dirtboy]

I wasn't saying in the context that the FBI knew at the time about the assasination conspiracy, but more in the context that subsequent events justified initial concerns about the group.