Televised political debates are usually a crucial part of political campaigns, although at times they often have more entertainment than political value. Here are some memorable quotations from a few American political debates over the past 30 years. Governor Sarah Palin and Senator Joe Biden Vice Presidential Debate, Washington University, St Louis, Missouri, October 2008
"Darn right. It was the predator lenders who tried to talk Americans into thinking that it was smart to buy a $300,000 house if we could only afford a $100,000 house. There was deception there, and there was greed and there is corruption on Wall Street ... Joe Six Pack, hockey moms across the nation, I think we need to band together and say never again. Never will we be exploited and taken advantage of again by those who are managing our money and loaning us these dollars." Sarah Palin
"But the notion that somehow, because I'm a man, I don't know what it's like to raise two kids alone, I don't know what it's like to have a child you're not sure is going to - is going to make it - I understand. ... I understand what it's like to be a single parent. When my wife and daughter died and my two sons were gravely injured, I understand what it's like as a parent to wonder what it's like if your kid's going to make it. I understand what it's like to sit around the kitchen table with a father who says, 'I've got to leave, champ, because there's no jobs here'." - Joe Biden
Outcome: It drew 70 million viewers and was the second most watched political debate after Reagan versus Carter in 1980. Voter polls suggested Mr Biden won, but Mrs Palin did better then expected, with few of the stumbling gaffes that had become a staple of late-night comedy shows. Critics claim that Mrs Palin seemed more poised and confident, and connected better with viewers, while Mr Biden was accused of being too passive.
Senator Barack Obama and Senator John McCain Presidential Debate, Belmont University, Nashville, Tennessee, October 2008 "In his short career, he does not understand our national security challenges. We don't have time for on-the-job training, my friend." - John McCain on Mr Obama's leadership qualities "It's true, there's some things I don't understand. I don't understand how we ended up invading a country that had nothing to do with 9/11 while Osama bin Laden and al Qa'eda are setting up base camps and safe havens to train terrorists to attack us." - Barack Obama's response
Outcome: Unexciting with some critics dubbing it "boring all around" and "downright dull". Mr McCain did not impress enough, with one observer saying it was "devastating and possibly electorally fatal" for him. Mr Obama was said to have come out marginally on top for substance, empathy, style and authority.
Governor George W Bush and Vice President Al Gore First Presidential Debate, Boston, October 2000 "It is time for a fresh start after a season of cynicism." - George W Bush "I may not be the most exciting politician, I will work hard for you every day. ... I will never let you down." - Al Gore Outcome: Going into the debate, the two men were running neck-and-neck in the opinion polls with only five weeks of campaigning left. During a 90-minute clash, they squared up to discuss issues ranging from taxation to foreign policy. Neither emerged as a clear winner, analysts agreed.
President George H W Bush and Governor Bill Clinton Presidential Debate, Michigan, October 1992 "Tonight I have to say to the president, Mr Bush: For 12 years you've had it your way. You've had your chance and it didn't work. It's time to change. I want to bring that change to the American people." - Bill Clinton "Watch out Middle America, Clinton is going to stick it right in your wallet." - George H W Bush
Outcome: As the third and final debate, it represented Mr Bush's last chance to make an impression to a national audience. Trailing badly in the polls, he showed more tenacity and willingness to attack Mr Clinton in a barrage of sparky exchanges. Mr Bush won the debate by a whisker that day, but did not convince the voters as it turned out.
Ronald Reagan and President Jimmy Carter Presidential Debate, Cleveland, Ohio, October 1980 "Next Tuesday all of you will go to the polls; you'll stand there ... and make a decision. I think when you make that decision, it might be well if you ask yourself: are you better off than you were four years ago?" - Ronald Reagan "I had a discussion with my daughter, Amy, the other day, before I came here, to ask her what the most important issue was. She said she thought nuclear weaponry ... and the control of nuclear arms." - Jimmy Carter
Outcome: Recorded the highest viewership for a political debate, exceeding 80 million. It was also the most important event of the presidential campaign, held one week before the election, and has gone down in history as the day the president lost the race. Mr Reagan, the consummate actor, came across as a confident, skilled orator, while Mr Carter's reference to consulting with his 12-year-old daughter was a misjudged disaster. Over the course of two hours, the race changed drastically, and what had been considered an extremely tight race with the president slightly ahead became a comfortable Republican victory for Mr Reagan. Nothing of that magnitude has happened since in any televised confrontations. * The National