Henry Fonda (Robert Leffingwell)
Charles Laughton (Sen. Seabright "Seab" Cooley)
Don Murray (Sen. Brigham Anderson)
Walter Pidgeon (Sen. Bob Munson)
Gene Tierney (Dolly Harrison)
Rene Paul (French Ambassador)
Bill Quinn (Sen. Hendershot)
Chet Stratton (Rev. Birch)
Betty White (Sen. Bessie Adams)
Sid Gould (Bartender)
Cay Forrester (President's Secretary)
Will Geer (Senate Minority Leader)
Michele Montau (Celestine Barre)
J. Edward McKinley (Sen. Hanson)
Malcolm Atterbury (Sen. Tom August)
Russ Brown (Nightwatchman)
Raoul de Leon (Sen. Velez)
Hilary Eaves (Lady Maudulayne)
Edward Andrews (Sen. Orrin Knox)
Tom Helmore (British Ambassador)
Eddie Hodges (Johnny Leffingwell)
Paul McGrath (Hardiman Fletcher)
George Grizzard (Sen. Fred Van Ackerman)
Paul Ford (Sen. Stanley Danta)
Franchot Tone (The President)
Peter Lawford (Sen. Lafe Smith)
Inga Swenson (Ellen Anderson)
Lew Ayres (The Vice-President)
Burgess Meredith (Herbert Gelman)