1. James Buchanan's failure to avert the Civil War.
  2. Andrew Johnson's decision just after the Civil War to side with Southern whites and oppose improvements in justice for Southern blacks beyond abolishing slavery.
  3. Lyndon Johnson's allowing the Vietnam War to intensify.
  4. Woodrow Wilson's refusal to compromise on the Treaty of Versailles after World War I.
  5. Richard Nixon's involvement in the Watergate cover-up.
  6. James Madison's failure to keep the United States out of the War of 1812 with Britain.
  7. Thomas Jefferson's Embargo Act of 1807, a self-imposed prohibition on trade with Europe during the Napoleonic Wars.
  8. John F. Kennedy's allowing the Bay of Pigs Invasion that led to the Cuban Missile Crisis.
  9. Ronald Reagan and the Iran-Contra Affair, the effort to sell arms to Iran and use the money to finance an armed anti-communist group in Nicaragua.
  10. Bill Clinton's relationship with White House intern Monica Lewinsky.

(Copyright 2006 by The Associated Press. All Rights Reserved.)