Read Katrina’s full column at the WashingtonPost.com.

What happens when a credible third party gets a real chance to appeal to voters? With 10 campaigning days left, we are seeing the results in the British election, in which the surge of Liberal Democrat leader Nicholas Clegg is driving ideas and policies usually excluded from Britain’s hidebound politics into the campaign debate — and, possibly, into real-world actions. Americans locked into our two-party system could learn a thing or two.

Given the opportunity to be heard by a national TV audience in Britain’s first-ever televised prime ministerial debates, Clegg turned in a stellar performance, mining widespread discontent with the establishment Labor and Conservative parties and emerging as a political superstar.

Even after a second debate in which Labor’s Gordon Brown and the Conservatives’ David Cameron engaged Clegg more aggressively in an effort to stop what some have dubbed "Cleggmania," the dynamics of the campaign — which have the Liberal Democrat emerging as a powerful, possibly king-making force in the election — have not fundamentally changed, and they probably won’t following the third debate on Thursday.

Clegg’s rise is inspiring for those of us on this side of the ocean who regularly rail against the ironclad consensus of excluded alternatives and managed expectations that are so familiar in America.

To read Katrina’s full column, please visit the WashingtonPost.com.