This is my favorite Tracy-Hepburn film and one of my favorite Frank Capra films. I recommend reading Capra's out-of-print biography, "The Name Above the Title" for the interesting story of the reaction to this film by official Washington in 1948.
Quite reminiscent of "Meet John Doe," the story tests the character of a man against the political power-brokers who want to use him for their own purposes. Ideals battle pragmatism in ways that still ring true 50+ years later.
Angela Landsbury is a wicked woman (can we call her a fem fa tale?) in an amazing performance foreshadowing her role in 1962's "Manchurian Candidate." Adolphe Menjou's sleazy political boss is about a greasy as they come.
All in all there is nothing like a Capra film to make me what to stick to my principles and listen to the people who really love me. Add to Capra's theme of the inherent wisdom of the people this first rate group of actors and you have two hours of time well spent.