I would bet Blackmun had assurances his character would be portrayed in a dignified and respectful way, and I would also guess he was allowed to see some early cuts of the film to make sure the storyline did not detract from the stature of the Supreme Court.

4. You ever seen Superman $#$# his pants? Case closed.

What a sight that would be! lol.

They should have given Clarence Thomas a role on the Amistad, whining about the lack of women.
Hehehe. I can see it now "Hey, who put the pubic hair in my buttermilk?!"
Badgers? We don't need no stinkin' badgers! But if you could show us something in a nice possum

In addition to retired Supreme Court Justice Harry Blackmun playing a Supreme Court Justice, a current U.S. Senator named Enest "Fritz" Hollings (D-SC) played a U.S. Senator in the movie CITY HALL (with Al Pacino), and lawyer/Urban League head Vernon Jordan played a law professor for a mock trial in the film ROUNDERS.

They should have given Clarence Thomas a role on the Amistad, whining about the lack of women.
What the $%*& is a Chinese Downhill?!?

I don't know why it would be completely out of the question for a former member of the Supreme Court to appear in a film. Other branches of the government have had actors/entertainers. President Reagan being the most obvious individual to point to as an actor in government. Senator Fred Thompson was a government attorney turned actor, who then became a US Senator, only to return to the acting field (in fact signing for a role while finishing his term.) Why should the courts be left out?

It doesn't seem like Spielberg really had to twist his arm at all. From the articles I've read, Justice Blackmun seemed honored to be given the opportunity.
http://www.law.harvard.edu/alumni/bulletin/backissues/fall97/classnotes/main.html
A lot of strange things happen in this world. Things you don't know about in Grand Rapids.