Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the government for a redress of grievances.
This is, in truth, one of the hardest choices on the whole list. So many films have examined our First Amendment freedoms, from Network to The People vs. Larry Flynt to Brazil.
But I'm picking George Clooney's Good Night and Good Luck, a film that succinctly and powerfully gets at one of the central ideas behind our Founding Fathers' entire philosophy of governance.
In a free society, a source of power must always be counterbalanced. Checks, balances, that whole thing. It works not only in terms of elected officials. So if you're going to have a wealthy and dominant federal and state governments ruling over citizens, if you're going to have corporations exerting their influence on these governments, you must have a free press exposing all the secretive and corrupt stuff that they do.
In Clooney's film, Senator Joseph McCarthy starts out with undue influence over the American discourse. One of the only roadblocks (and there were more than a few) to his continued dominance was Edward R. Murrow and the microphone provided to him by CBS News. (The film likewise explores the difficulty of Murrow fighting the powerful while employed by a powerful media conglomerate himself.)