Presidential debate milestones [infographic]

America’s presidential debate season kicks off on September 29. From the contests at which Abraham Lincoln made moral arguments against slavery to recent events at which candidates delivered memorable sound bites, debates have seen many changes.

Significant events at presidential debates in 1858, 1948, 1960, 1976, 1980, 1984 and 1992 (Photos: © Getty Images and AP Images)