It happened in New Hampshire at a debate just before the primary in 1980. Debate moderator Joe Breen was trying to lock Reagan out of the dialogue by shutting off his microphone.
When Breen requested that Regan's microphone be silenced the look on Reagan's faced suddenly changed to one of near outrage. The usually genial Reagan grabbed the mike, stood up and asked "Is this on?" Seeing that he was still amplified, Reagan shot back "I paid for this microphone, Mr. Green!"
Forget that Reagan got the moderator's name wrong. Forget why Breen saw fit to attempt to silence Reagan. The audience went wild in support of Ronnie and this clip and soundbite were seen and heard everywhere, changing the tide in the campaign.
People saw that Reagan was human, that he was real, that he was willing to fight for his beliefs and the right to express those beliefs.
Let's face it we've all had a moment when some officious functionary has attempted to push us around - and we've all longed to fight back. Reagan captured that feeling in all of us and fought back.
From that point on the mantra "let Reagan be Reagan" guided Ronnie's campaign to victory.
Watch the entire clip of this classic campaign moment here.