Presidential Debate Impact Debatable

Since World War II only 1960 and 2000 seems to have changed race

An analysis by the Gallup organization says the presidential debates have had little to no impact on voter preferences during the debate periods in 1984, 1988, and 1996.

The 1980 and 1992 debates may have influenced voter support for the third-party candidates running in those elections; however, they do not appear to have altered the structure of the races for the two major-party candidates.

• In 1980, third-party candidate John Anderson fell from 15% support prior to his only debate (which was with Ronald Reagan) in late September to only 8% support by mid-October. However, given the long span between polls during this period, and the downward trend in Anderson’s support prior to the debates, it is unclear whether his debate with Reagan was a factor.
• In 1992, Ross Perot’s generally well-reviewed debate performances (close to half of Americans thought he won the first debate, and the plurality thought he won the third debate) were no doubt part of the reason he catapulted from a 10% level of support prior to the first debate to 17% support after the last debate.

The 1976 and 2004 debates seem to have made the races more competitive, but they did not change the fundamentals of the races; the candidate leading before the debates eventually won the elections.

By contrast, the debates of 1960 and 2000 seem to have been associated with meaningful shifts in the horse races for those elections, whereby the ultimate winner moved from a deficit position to front-runner.

(In 1964, 1968, and 1972, incumbent president Lyndon Johnson and Republican nominee (and later President) Richard Nixon refused to debate their opponents, so no presidential debates were held in those years.)