The major US presidential candidates, Democrat Barack Obama and Republican Mitt Romney, will hold their first campaign debate on Wednesday evening in Denver, Colorado.
One of the first political debates in the U.S. took place in Illinois, in 1858. Senatorial candidates Abraham Lincoln and Stephen Douglas stood on this rock and argued over slavery. Lincoln lost the race but went on to win the presidency two years later. Ten thousand people watched the debate in this park.
Fast forward 100 years and many more would watch a presidential debate on a fairly young technology called television.
A tanned Senator John F. Kennedy visually overpowered an uncomfortable and sweaty Vice President Richard Nixon. Journalist Howard K. Smith moderated the debate.
“We offered Nixon make-up, but in those days TV was still new to politicians and it was considered effeminate to have. He refused it," said Smith.
Kennedy won the election, some say, partially due to the debate.
It was 16 years before another presidential debate would be held, and it appeared costly for the incumbent. President Gerald Ford made an understatement about Russia when facing challenger Jimmy Carter, and he eventually lost the election.
“There is no Soviet domination of Eastern Europe and there never will be under a Ford administration," said Ford.
In 1988, Democratic Vice Presidential Candidate Lloyd Bentsen scored high in this retort to his Republican rival Dan Quayle. First, Quayle.
“I have as much experience in the Congress as Jack Kennedy did when he sought the Presidency," said Quayle.
“Senator I knew Jack Kennedy. Jack Kennedy was a friend of mine. Senator you're no Jack Kennedy," answered Bentsen.
The Republicans won the election anyway. George H.W. Bush became president.
In 1992 he ran for re-election.
In one debate, television cameras caught him glancing at his wristwatch - as if uninterested. He lost.
Debates can be a tipping point in close elections. That's because they are the first time Americans see the candidates together - on the same stage - discussing the same issues, but explaining why their ideas are better than those of their opponents."
Every four years, presidential candidates spar at three debates - the first debate attracts the largest audience. Another is a town hall with questions from the audience. President Obama appeared relaxed in that debate four years ago.
But many agree Mitt Romney is a skilled speaker, especially when he's prepared.