Britain's first foray into televised election debates had a familiar look to Americans accustomed to the political ritual – it was just as stilted, stage-managed and occasionally revealing as the US version. But the 90-minute prime-time encounter Thursday, the first of its kind in Britain, gave millions of British viewers the sort of close-up view of their candidates that Americans now consider a campaign tradition. Prime Minister Gordon Brown of Labor and the leaders of the top two opposition parties – Conservative David Cameron and Liberal Democrat Nick Clegg – bickered frequently and sometimes interrupted one another in an earnest debate that would be considered relatively lively by US standards. The encounter took its cue from televised US presidential debates, which have become a centerpiece of American campaigns in the 50 years since the first encounter in 1960 between Democrat John Kennedy and Republican Richard Nixon. Like their American counterparts, the participants carefully negotiated a set of rigid ground rules, prepped for the debate with teams of consultants – including some American political veterans – and cautiously tried to avoid a political gaffe that could sink their campaigns. Here are a few of the similarities with US presidential debates, and some key differences: * The three candidates stood rigidly at podiums before an invited audience that asked them questions and remained respectfully silent during the answers – all standard fare in general presidential debates in the United States. The frequent debates during campaigns for US presidential party nominations – Barack Obama and Hillary Clinton debated more than 20 times while pursuing the 2008 Democratic presidential nomination – are often more raucous affairs with loud audiences of supporters. * The British candidates seemed more inclined to actually answer the questions than American debaters, who habitually use queries they don't like as a jumping-off point for lengthy excerpts of their standard campaign speeches. Each tried to offer earnest summaries of their parties' stances on immigration, education, crime and the economy, and they personalized their campaign pitches with references to real people – a standard ploy of US politicians. US presidential debates often elevate personal image and style above substantive political arguments – the first debate in 1960 is most remembered for the personal contrast between a vibrant and confident Kennedy and the pale and perpetually ill-at-ease Nixon, plagued by a 5 o'clock shadow. Many of the most memorable moments in US presidential debates involve moments that reflected personality – Democrat Al Gore's exasperated sighs in 2000, or the first President George Bush's impatient glance at his watch in 1992. * The moderator allowed candidates to engage one another after making initial statements, and they did. Clegg and Cameron were in attack mode against Brown's Labor government, and Clegg tried to paint Cameron as another defender of the status quo with Brown. While the format was different, the sometimes lively exchanges were nothing new for politicians used to rowdy verbal jousting and open heckling each week when the prime minister and opponents in Parliament openly engage in “Prime Minister's Questions” – a tradition with no American equivalent. When President Barack Obama traveled to a Republican congressional retreat earlier this year to engage opponents in a question-and-answer session, it was viewed as a groundbreaking move born of his desperation to revive a stalled healthcare overhaul. * None of the candidates appeared to blunder into a fatal gaffe that could turn the campaign, like Republican Gerald Ford's 1976 pronouncement that eastern Europe was not dominated by the Soviet Union. That statement deepened his image as a bumbler and helped lead to his defeat by Democrat Jimmy Carter. * It was unclear how many viewers the debate might attract, but as the first televised political showdown in British history the audience might be huge. In the United States, debates have become so ingrained that the audiences –and perhaps the impact – have begun to shrivel. The most watched presidential debate in the 2008 campaign between Obama and Republican John McCain drew 63 million viewers, well behind the record of nearly 81 million in 1980.