Robert A. Leffingwell (Henry Fonda) is nominated to be Secretary of State of the United States. Leffingwell has been hand-picked by a second-term President (Franchot Tone), who is seriously ill.
The Senate, using its advise and consent powers, must either approve or deny the appointment. Under the watchful eye of Vice President Harley Hudson (Lew Ayres), there is a heated battle on the Senate floor between supporters and opponents of the President.
The senators fighting it out in public and in private include the veteran Dixiecrat-like Senator Seabright Cooley (Charles Laughton) of South Carolina, who despises Leffingwell for personal as well as political reasons, and Majority Leader Senator Bob Munson (Walter Pidgeon) of Michigan, the president's strongest ally. A committee appointed to assess the nominee is headed by freshman Utah Senator Brigham Anderson (Don Murray), who finds himself blackmailed by Wyoming Senator Fred Van Ackerman (George Grizzard). To neutralize Anderson, who wants Leffingwell's name to be withdrawn, Van Ackerman threatens to dredge up a homosexual incident in Anderson's past, which results in Anderson's suicide.
Herbert Gelman (Burgess Meredith) is a witness who testifies that Leffingwell has a Communist past.