US elections: Top ten moments in US debates Running for Republican vice-president in 1988, the youthful Dan Quayle had a tendency to compare his experience to that of John F. Kennedy. When Quayle did so in a debate, his Democrat rival Lloyd Bentsen shot back: "Senator, I served with Jack Kennedy, I knew Jack Kennedy, Jack Kennedy was a friend of mine. Senator, you're no Jack Kennedy. It was perhaps the greatest put-down in debate history, but Quayle was still elected as running-mate of the first George Bush. Four years later, President Bush learned the cost of "gesture politics." He was criticised for making a prominent show of looking at his watch while his young challenger Bill Clinton answered a question. In 2000, Al Gore sighed relentlessly while the younger George Bush spoke. It conveyed an air of elitist condescension and may have cost Gore enough votes to lose him the bitterly-contested election. Barack Obama is not always good with words. In New Hampshire in 2008, Hillary Clinton was asked if Obama was more personable than her. She responded with a joke and a smile, but a stern Obama, looking down at his notes, said coldly: "You're likable enough." The dismissive comment was criticised as condescending and arrogant and two days later he lost that primary as female voters backed Clinton in larger numbers than expected. John McCain, the Arizona senator who spent the late 1960s as a POW in Vietnam, has a reputation for his one-liners. He delivered one of his best during the Republican primary campaign four years ago. In case you missed it, a few days ago Senator Clinton tried to spend $1 million on the Woodstock Concert Museum. Now, ladies and gentlemen, I wasn't there. I'm sure it was a cultural and pharmaceutical event. I was tied up at the time. And Rick Perry, the Texas governor, had the most embarrassing brain-freeze in debate history in the Republican primaries earlier this year. Saying that as president, he would abolish three federal agencies, he then named commerce and education - but could not recall the third, even as his embarrassed rivals offered suggestions. "Oops," he said after a few agonising seconds. It was energy, for the record.