FACTBOX: Recessions and presidential elections

(Reuters) - Economic downturns have often torpedoed the re-election hopes of sitting U.S. presidents or the White House aspirations for the nominees of incumbent parties, especially if they coincide with an election year.

Many analysts currently forecast that the U.S. economy will fall into a recession this year, which could spell trouble for presumptive Republican nominee John McCain.

Following are some facts about U.S. presidential contests and recessions in the 20th century.

1920: A particularly hard recession starts in January and lasts 18 months. The nominee for the incumbent Democratic Party, James Cox, loses that year to Republican Warren Harding.

1932: Economy in throes of "Great Depression" that started in 1929. Sitting Republican President Herbert Hoover loses to Democrat Franklin Roosevelt.

1948: A recession begins in November that lasts for 11 months. Democrat Harry Truman defies the trend by winning re-election but was perhaps lucky as the recession only sank in the same month voters went to the polls.

1960: A mild recession begins in April and lasts for 10 months. Richard Nixon, the incumbent Republican Party nominee and sitting vice president, loses to Democrat John Kennedy.

1980: A six-month recession starts in January, kicking off a miserable political year for Democratic President Jimmy Carter, who loses in his re-election bid to Republican Ronald Reagan.

1992: A recession begins in July of 1990 and lasts for eight months, well before the 1992 election contest between Republican President George H.W. Bush and Democratic challenger Bill Clinton. But people's memory of the downturn is long and it is widely seen as key factor in Clinton victory.

(Sources: National Bureau of Economic Research; www.whitehouse.gov/history/presidents; "Franklin Delano Roosevelt" by Roy Jenkins; Federal Reserve Bank of Minneapolis)

(Compiled by Ed Stoddard in Dallas; Editing by David Wiessler)