John Adams, Opera, and Politics
Anyone who says that artists don't belong in politics betrays their ignorance of history and tradition. Composers have always commented on the social issues of their day and acted as society's conscience.
Mozart's operas transgressively mocked the class system. Much of Beethoven's greatest music, including Fidelio and his Third and Ninth Symphonies, was explicitly political. Verdi was an ardent advocate of Italian independence and unification, even serving in parliament. Hindemith's Mathis der Maler was such a obvious critique of the new Nazi regime that Goebbels banned it. We won't even get into the complicated relationship between Shostakovich and Stalin.