Basically, a fringe left-wing group had (mostly) done the job of American institutions when those failed, and revealed a conspiracy to the public. The “commies” were not (just) plotting against the U.S., but protecting it against its own government! That’s wilder than most conspiracy theories.
Speaking of COINTELPRO...
http://en.wikipedia.org/wiki/Citizens%27_Commission_to_Investigate_the_FBI
Basically, a fringe left-wing group had (mostly) done the job of American institutions when those failed, and revealed a conspiracy to the public. The “commies” were not (just) plotting against the U.S., but protecting it against its own government! That’s wilder than most conspiracy theories.