Back in July 2004 Hollywood actors, writers, and directors joined with MoveOn to campaign against President Bush. Ed Asner, Danny Glover, Al Franken, Kevin Bacon, Margaret Cho, Woody Harrelson, Scarlett Johansson, Alicia Silverstone, Rob Reiner, Errol Morris, and Aaron Sorkin wrote, directed, and starred in TV spots for MoveOnPAC.

MoveOn's Hollywood Connection THE LEFT COAST REPORT: A Political Look at Hollywood
Tuesday, September 18, 2007 8:27 PM
http://www.newsmax.com/hirsen/MoveOn/2007/09/18/35652.html

Saturday, Jul. 03, 2004
The liberal advocacy group MoveOn.org has already proved to be a force in the campaign to defeat President Bush, but it is about to get a big infusion of help from Hollywood. MoveOn's Political Action Committee, MoveOnPac, last week announced that documentary filmmaker Errol Morris (The Fog of War) will produce a series of campaign ads. The group is also about to announce that it has enlisted an all-star roster of directors, writers and Hollywood actors to make ads for the group. One is directed by Rob Reiner and written by West Wing creator Aaron Sorkin. Another is directed by indie-film veteran Allison Anders (Gas Food Lodging) from a script by radio lefty Al Franken. Comedian Margaret Cho wrote and directed an ad, another stars Danny Glover, and an animated spot features the voices of Scarlett Johansson (Lost in Translation), Kevin Bacon and Ed Asner. Two more ads are in production, one written and directed by Woody Harrelson and the other starring Alicia Silverstone.

I'm Rob Reiner, and I Approve this Message Moveon.org, a political advocacy group, has enlisted the help of popular culture's most talented celebrities in the war to defeat Bush in 2004 By MATTHEW COOPER
http://www.time.com/time/election2004/article/0,18471,660923,00.html