While there have been many candidates for the presidency who have run without being nominated by one of the major political parties, very few have won more than 1 million votes. Fewer still have won electoral votes.

On the other hand, some third-party candidates have tapped into dissatisfaction among the natioon's voters with both major parties and won sizeable numbers of the popular vote. Insome cases they've won a number of states.

For example, when Theodore Roosevelt ran under the progressive (Bull Moose) banner in 1912, he captured 28 percent of the popular vote and 88 votes in the Electoral College.

Twenty years later, Dixiecrat Strom Thurmond won 39 electoral votes from five Southern states in 1948. George Wallace, running as the American Independent Party nominee in 1968, won 26 electoral votes from Southern states.

Independent Ross Perot won 19 percent of the popular vote in 1992, but he failed to win a single state.

Here's a look at the major third-party candidates in U.S. history:

• Anti-Masonic Party, 1832: William Wirt
• Liberty Party, 1844: James G. Birney
• Free Soil Party, 1848: Martin Van Buren
• American Know-Nothing Party, 1856: Millard Fillmore
• Greenback Party: 1876: Peter Cooper
• Greenback Party: 1880: James B. Weaver
• Prohibition, 1884: John P. St. John
• Peoples' Party, 1892: James B. Weaver
• Socialist Party, 1900-12; 1920
• Progressive (Bull Moose) Party, 1912: Theodore Roosevelt
• Progressive Party, 1924: Robert M. La Follette
• Socialist Party, 1928-49: Norman Thomas
• Union Party, 1936: Robert Lemke
• States Rights (Dixiecrats), 1948: Strom Thurmond
• Progressive Party, 1948: Henry Wallace
• American Independent Party, 1968: George Wallace
• American Party, 1972: John Schmitz
• None (Independent), 1980: John Anderson
• None (Independent), 1992: Ross Perot
• Reform Party, 1996: Ross Perot
• Green Party, 2000: Ralph Nader
• Independent Party, 2004: Ralph Nader
• None (Independent), 2008: Ralph Nader