In their first attempt at televised debates, British party leaders learned a lesson that has been painfully clear to American politicians for years -- the high-stakes encounters can change a campaign.
While the introduction of U.S.-style debates drew criticism about the Americanization of British politics, the final weeks of the race for the May 6 election have been dominated by the influential showdowns.
In U.S. presidential campaigns, debates have often been significant milestones, beginning with the first -- the 1960 encounter between Democrat John Kennedy and Republican Richard Nixon that helped turn the race for Kennedy.
In Britain, Nick Clegg's Liberal Democrats have surged in popularity since his strong performance in the first televised debate two weeks ago. That has increased the chance they could be kingmakers in a hung Parliament where no single party has control -- something that has not happened since 1974.
Clegg tried to portray himself during Thursday's debate, the last of the three, as a leader who was above the fray.
"Can I get beyond this point-scoring?" he asked at one point as his rivals -- Prime Minister Gordon Brown of Labour and Conservative David Cameron -- savaged each other's economic and tax policies. "Here they go again," he said later.
Brown went on the offensive in hopes a strong debate showing would help his party recover after he called a supporter "bigoted" Wednesday in a campaign-trail blunder.
"There is a lot to this job, and as you saw yesterday I don't get all of it right," he said in the first line of his opening statement.
Like U.S. President Barack Obama and many other U.S. politicians, who are now debating a financial regulatory bill in the U.S. Senate, the three British leaders took frequent aim at big banks and promised tougher regulations.
"We'll need to break up the banking system so that irresponsible bankers can never again put your savings and businesses at risk," Clegg said, calling for no bonuses for bank directors and board members.
Cameron promised to "fix our banks, tax them to get our money back, regulate them and get them lending again." He called for giving the Bank of England the power to regulate banks and called for a bank levy.
Brown said he took immediate action to keep the banking crisis from becoming a calamity. "I will say to these bankers we will never allow them to act in an irresponsible and unfair way again."
Brown, who learned firsthand about the impromptu dangers of American-style, man-in-the-street campaigning, did not delve into his campaign-trail gaffe after his opening remark.
Brown was unwittingly caught by a microphone complaining about Gillian Duffy, a 65-year-old widow who challenged the government's immigration policy. "She's just sort of a bigoted woman," Brown told aides later.
When he learned it had become public, a mortified Brown rushed back to make a private apology to Duffy.
In the 2008 campaign, Obama's offhand comment to an Ohio plumber on the street three days before the final presidential debate made "Joe the Plumber" a national celebrity and centerpiece of the campaign's last days.
Obama told Joe Wurzelbacher his tax policies would help "spread the wealth around," prompting Republican candidate John McCain to put Obama on the defensive with repeated references to "Joe the Plumber" throughout the final debate.
Brown employs U.S. tactic
Under heavy attack for his economic policies from both Cameron and Clegg, cameras showed Brown repeatedly using a favorite tactic of American politicians of all parties -- the disappointed, frowning shake of the head in disagreement.
It was probably a better response than Democrat Al Gore's loud exasperated sighs during his first debate with Republican George W. Bush in 2000 -- a response that reinforced some voters' doubts about Gore's likability.
Cameron, who could replace Brown as prime minister if his party wins, joined Brown in ganging up on Clegg in the second debate, but the focus Thursday was often on Cameron's heated exchanges with Brown.
Cameron used the same terms as U.S. conservatives in outlining his party's economic platform, saying they would "reward work and tackle welfare dependency" and promising he would never join the euro and would keep the pound as British currency.