Does it matter when national debates are opened up to third-party contenders?

The news from Britain says "yes" — emphatically.

Former Nation intern Nick Clegg, achieved political superstar status this week when, with a stunning performance in the first nationally-televised debate of Britain’s 2010 election campaign, the leader of Britain’s third party, the Liberal Democrats, trumped Prime Minister Gordon Brown of the ruling Labour Party and Conservative Party leader David Cameron.

Afforded an opportunity to be heard by a national audience as the campaign for the May 6 election hits its stride, Clegg dismissed the two traditional parties of government as incapable of delivering meaningful change at a time when British voters have grown frustrated with political scandals, economic instability and foreign policies that have aligned Britain with the U.S. in Iraq and Afghanistan.

Clegg was the only one of the three candidates who, as a member of parliament, opposed going to war in Iraq and he has been a steady critic of assaults on civil liberties and the insider politics played by the Labour Party of Tony Blair and Gordon Brown. At the same time, he has challenged the notion that Cameron has really changed the direction of Margaret Thatcher’s Tory party.

Dismissing Brown and Cameron as the faces of “two old parties,” Clegg portrayed the election as “a fantastic opportunity to do things differently.”

“So don’t let anyone tell you the only choice is the same old politics,” he told voters. “We can do something new, something different.”

Britain liked what it heard.

There was no debate about the fact that Clegg, whose center-left party is far smaller than Labour and the Conservatives, won the debate. Nor was there any question that the inclusion of a credible third-party contender in a national debate had shifted the dynamic of the election campaign in radical ways.

The headlines said it all:

"Nick Clegg Seizes His Moment in the TV Spotlight," announced the liberal Guardian newspaper, which explained: "Lib Dem leader makes powerful pitch as he depicts his party as a significant change from Labour and the Conservatives."

"Nick Clegg’s Star Rises in Great Showdown," announced the the more right-leaning Telegraph newspaper.

"Nick Clegg Triumphs," declared the conservative Spectator magazine after Thursday’s debate began a cycle of televised clashes between Clegg, Brown and Cameron prior to the May 6 election.

The conservative Times of London, in an an editorial headlined "The Other One Wins," declared that: "Nick Clegg took his chance and changed a two-man competition into something that looks more like a three-horse race."

The BBC speculated about "Clegg’s emergence as a serious player in this election."

The voters agreed.

Every post-debate poll counted Clegg as the big winner.

In a Guardian/ICM poll, for instance, Clegg emerged as "the overwhelming winner, with 51 percent who watched saying he came out on top. Cameron, whose party has been leading in the polls, was picked by 20 percent, Brown, by 19 percent.

Does this mean that Clegg will be prime minister?

No, at best the fellow who did a turn as a Nation intern in 1990 before beginning a rapid rise in European politics has gotten himself in the running.

The Guardian may headline an article with the declaration "Nick Clegg Now in Contention as Potential PM," but the Liberal Democrat (which has a long history in parliament but has not produced a prime minister since 1922) is going to have to turn in a lot more stellar performances before he and his party break the long two-party grip on British politics.

Still, the lesson that a fresh face with a genuine reform message — Clegg and the Liberal Democrats are proposing radical changes in the electoral and governing processes with an eye toward developing "a new political system for the 21st century" — can change the political dynamic is clear.

It’s a lesson that ought to be translated to the U.S., not merely in the 2012 presidential election but in this year’s congressional and state elections. Unfortunately, as Jeff Cohen, the founding director of the Park Center for Independent Media at Ithaca College notes, what made the British debate exciting — the inclusion of an alternative voice — is exactly what a the two major parties in their U.S. and their media allies work so hard to prevent with debate commissions and ridiculous rules for who is and is not "credible."

American political debates are robbed of life and meaning by the exclusion of credible independent and third-party contenders. This year’s campaigns for U.S. House and Senate seats, as well as for three dozen governorships around the country, will feature candidates from many parties and perspectives. Moderate Republicans such as former Rhode Island Senator Lincoln Chafee are mounting exciting independent campaigns. There’s talk that Florida Governor Charlie Crist may exit the GOP and seek a Senate seat as an independent. Tea Party activists are preparing third-party bids, as are Libertarians, Greens and others.

If we open our debates up, as Britain has begun to do, we’ll open up our politics. And that’s the best tonic for democracy.