Ahhhh,,,a return to the good old days...
The Black Panther Coloring Book
This is but one horrific example of the tactics used by the Federal Bureau of Investigation to stifle legitimate dissent and violate the civil rights of political groups that the administration dislikes. Along with the anti-war movement, the Nixon White House targeted the civil rights movement for disruption, using on-campus informants to infiltrate and in many cases to disrupt legal protests and activism.
This coloring book, which was purported to be from the Black Panthers, had actually been rejected by them when it was brought to them by a man later revealed to have intelligence connections. Not to be troubled by the fact that the Panthers found the coloring book revolting, the FBI added even more offensive illustrations, and mass mailed it across America. It so infuriated the white population that they stopped listening to the legitimate grievances of the black people.
While it can be argued that such an action did not technically violate the right of the Black Panthers to free speech (even as it sabotaged the willingness of the people to listen), it is apparent than such a divisive act violated the right of the people, black and white, to peacefully assemble.
At the time, I asked my parents if it didn't seem odd to have a book purported to be by blacks for black children mailed to a white household, but I was outvoted in what was a functionally democratic household (except for the dictator from MIT). But heck, most of us still thought Oswald acted alone then as well.
I had thought the actual coloring book lost forever, relegated to a mere footnote in the Congressional inquiry into COINTELPRO, when the wonder that is the internet brought it into the light again.