The 2010 TIME 100

Yukio Hatoyama, 63, does not look like a revolutionary. Scion of an old political family and heir to a fortune made in tires, the Japanese Prime Minister was entirely predictable in his early career as a rising politician in the conservative Liberal Democratic Party (LDP).

But while no revolutionary himself, Hatoyama has become the leader of a revolution of a kind. He left the LDP in 1993 and started a new party, which, after merging with other groups, finally broke the LDP's virtual monopoly on power in 2009. The party's goals — a more equal partnership with the U.S., more power to elected politicians, more transparency — are all commendable. But even if they are not swiftly and entirely achieved, Hatoyama has helped change his country from a de facto one-party state into a functioning democracy. That is reason enough for celebration.

Buruma is Henry R. Luce Professor of Democracy, Human Rights and Journalism at Bard College

TIME 100 Social-Networking Index: 2,228