Interesting-----The 8 Biggest Unforced Errors in Debate History

The 8 Biggest Unforced Errors in Debate History - POLITICO Magazine:
#4.
1984:
Mondale lets Reagan’s one-liner negate a serious weakness
During 1984’s first debate, Reagan, then 73, aroused concern when he seemed to have trouble remembering his answers or following the questions.
He stumbled over his words and lacked clarity with each statement. 
His opponent, former Vice President Walter Mondale, was crisp and sharp. In contrast, Reagan rambled through his closing statement to the alarm of his advisers.
Lou Cannon wrote that Reagan left the stage admitting to campaign adviser Stu Spencer “that he had flopped.”
The Wall Street Journal’s headline the next morning captured the zeitgeist: “New Question in Race: Is Oldest President Now Showing his Age?”
Fortunately for Reagan, he came back with a vengeance.
In a later debate, when Baltimore Sun journalist Henry Trewitt asked Reagan if his age would prevent him from fulfilling the rigors of the presidency, Reagan had a quip for the ages:
“I will not make age an issue in this campaign. I will not exploit, for political purposes, my opponent’s youth and inexperience.”
The audience erupted in laughter, including Mondale, which completely undercut the seriousness of the underlying charge."