TUESDAY, OCT. 1 at 7:00PM

What happens when the President of the United States is unable to fulfill the duties of the office due to illness, incapacity or death? Incredibly, it is a question that went without a definitive answer for much of American history. And despite the assassinations of three sitting presidents (Lincoln, Garfield, McKinley) and the deaths of four more in office (Harrison, Taylor, Harding, FDR), it wasn’t until 1963 that the ambiguity in the Constitution was finally deemed worthy of redress.

One hour before our live coverage of the CBS News Vice Presidential Debate on October 1, THE AMERICAN EXPERIENCE presents The American Vice President, exploring the little-known story of the second-highest office in the land, tracing its evolution from a constitutional afterthought to its current position of enormous political consequence.