Republican nominee Donald Trump and Democratic nominee Hillary Clinton speak during the second presidential debate at Washington University in St. Louis, Oct. 9, 2016.
AP Photo / Patrick Semansky
From the 1993 Pulitzer Prize-winning portfolio by AP photographers, President Bush, left, talks with independent candidate Ross Perot as Democratic candidate Bill Clinton stands aside at the end of their second presidential debate in Richmond, Va., Oct. 15, 1992.
AP Photo / Marcy Nighswander
Cowboys doff their big hats at Laramie, Wyo., Sept. 18, 1932, as the Roosevelt Special stopped for a short time. New York Governor Franklin D. Roosevelt, center, was on the campaign trail as the Democratic nominee for president of the United States.
Television debates were an innovation in the 1960 presidential campaign. Sen. John F. Kennedy and Vice President Richard M. Nixon face off in the fourth and final of these debates in New York, Oct. 21, 1960.
Democratic presidential nominee Michael Dukakis rides in a new General Dynamics' M1A1 battle tank in Sterling Heights, Mich., Sept. 13, 1988. The photo op was meant to demonstrate the Massachusetts governor's defense credentials, but the images of Dukakis aboard the tank were widely ridiculed.
AP Photo / Michael E. Samojeden
President Harry S. Truman holds up an Election Day edition of the Chicago Daily Tribune, which, based on early results, mistakenly announced "Dewey Defeats Truman" on Nov. 4, 1948. The president told well-wishers at St. Louis' Union Station, "That is one for the books!"
AP Photo / Byron Rollins
Democratic presidential candidate Sen. Bernie Sanders, I-Vt., and his wife Jane order lunch at the Van Dam diner, April 9, 2016, in Queens, New York.
AP Photo / Mary Altaffer
President Ronald Reagan works the crowd of well wishers shortly after he landed at El Toro Marine Corps Air Station, Sept. 2, 1984, in Irvine, Calif., kicking off his 1984 general election campaign.
AP Photo / J. Scott Applewhite
President Barack Obama, right, is lifted off the ground by Scott Van Duzer, owner of Big Apple Pizza and Pasta Italian Restaurant, during an unannounced stop in Ft. Pierce, Fla., Sept. 9, 2012.