(FORTUNE Magazine) – On April 28, 1938, the Daily Worker, official organ of the Communist Party USA, published the names of dozens of show-business celebrities who had signed a petition supporting ''the recent Moscow trials of the Trotskyite-Bukharinite traitors.'' Instant disclaimer: We lead with this gripping detail only to supply a bit of historical perspective. Your servant would not dream of attributing comparable Stalinoidal depravity to the present generation of bubble-headed show-biz liberals. Having recently done a fair amount of boning up in Nexis, your servant now posits that movieland is even more politicized than it was in the Thirties. To be sure, real Reds are becoming nonexistent. At least they are in Hollywood -- Ed Asner, a.k.a. Lou Grant, was recently forced to travel to Managua to find the kindred spirits he was looking for. (He was hoping to attend the Sandinistas' victory celebration.) Oliver Stone, Sidney Pollack, and Spike Lee have made the scene at the Havana Film Festival. And it was in Cuba that Robert Redford had his now famous get-together with Fidel. Along with George Lucas and Francis Ford Coppola, Redford was there in support of a state- promoted film foundation run by anti-yanqui novelist Gabriel Garcia Marquez. Recently collared by a writer for the New Republic, Bob took the line that he was interested only in filmic art, not in politics. Asked whether he would therefore feel free to attend film conferences in South Africa, his immortal answer was: ''Well, well, I don't know. That's not a problem, so I don't have to face it.'' Back home, the political culture of Hollywood remains unbudgeably left- liberal, and television has created new symbiotic ties between the stars and liberal politicians. So now the glitterati get cast as expert witnesses and asked to testify before Congress. Paul Newman has appeared more than once , for the dovish Center for Defense Information; he also made a terrific cameo appearance in the Senate gallery 2 1/2 years ago, lending his moral authority to the forces opposing the Strategic Defense Initiative. Alas, VP Bush ruined his day by casting a tie-breaking vote for SDI. Another recent congressional testifier is John Denver, who offered the House of Representatives a pro-planet perspective on the National Environmental Education Act. Also Meryl Streep, who advised the Senate subcommittee on children, family, drugs, and alcoholism about the menace of pesticides in applesauce messily eaten by little kids. Laboring to find questions this expert witness could answer, Tom Harkin of Iowa earnestly asked if Meryl would be willing to ''reach out'' to farm families. Democratic Senator Joe Lieberman of Connecticut, who had evidently lived a life of utter self-abasement up to this point, told Meryl: ''I am prouder than I have ever been listening to you today.'' A theme weirdly recurring in our Nexis search was the propensity of actors to take up causes suggested by their latest scripts. Sally Field became an active advocate of unionism as a result of performing in Norma Rae, and in 1988 got to introduce Michael Dukakis to a union audience. Mike Farrell became a critic of U.S. foreign policy after years of absorbing pacifist doctrine by playing the part of Captain B. J. Hunnicut in M*A*S*H. Mike has lectured on foreign policy at the University of Wisconsin, an institution still scared to invite Jeane Kirkpatrick. Martin Sheen, who appeared in Apocalypse Now, seems to have been even more radicalized, or at least one so concludes on the basis of his passionate-protest arrest record (he has been hauled in more than 20 times), not to mention his career as honorary mayor of Malibu, California. During this stint, he proposed the town as a refuge for America's homeless, a move said to threaten local real estate values. To be sure, he arguably enhanced them by declaring the place a nuclear-free zone.