Bogart organized a delegation to Washington, D.C. He called the Committee for the First Amendment, against the House Un-American Activities Committee's harassment of Hollywood screenwriters and actors. He subsequently wrote an article "I'm No Communist" in the March 1948 edition of Photoplay magazine in which he distanced himself from The Hollywood Ten in order to counter the negative publicity that resulted from his appearance. Bogart wrote: "The ten men cited for contempt by the House Un-American Activities Committee were not defended by us."
NOTE: If you are curious about learning further about Bogart’s part in this matter, I recommend reading “Hollywood Party” by Kenneth Lloyd Billingsley. The book tells about how Communist infiltrated Hollywood and the movie’s union. It is a really good book.