Leading article: A politician who kept his principles

Every generation produces a clutch of politicians who make a name for themselves quite independent of any position they might hold. Germany's former foreign minister and chairman of the Green Party in the Bundestag is one such. For years now, he has been known simply as Joschka.

The name immediately conjures up the individual: burly, with tousled hair prematurely grey, Joschka Fischer was always his own man. This week, he took part in what is likely to be his last meeting of the Greens' parliamentary grouping in the Bundestag. He is to take a year out of politics, lecturing in international relations at Princeton. His farewell has been the occasion for fulsome tributes anticipating the end of a unique career.

Joschka Fischer was undoubtedly good for Germany. He was an adventurer who brought flashes of colour into the staid monotony of the country's politics. From an early age, he was a rebel with a cause; a gifted propagandist and orator who set out to incite revolt. The Sixties could have been made for him. Always more of a doer than a thinker, he flourished in the political and intellectual ferment.

But Joschka Fischer's greater distinction was to understand when the Sixties were over and transfer successfully to the mainstream. As an early member of the Green Party, he quickly sought and won elected office. Eschewing formality, he nonetheless developed a respect for order in politics. He became not only Germany's most recognisable public figure, but easily its most popular politician, too.

He raised the Green Party out of the doldrums it sank into after the high-wire act of Petra Kelly's leadership, and established it as a party able to combine sound thinking with idealism. He gave it a credibility that has made Green politics a force not only in Germany, but in Europe. When Joschka Fischer first took the party into coalition with Gerhard Schröder's Social Democrats - a controversial step for some of the party's more "alternative" types - he was able to show time and again that principle need not be sacrificed to the reality of power. As foreign minister, he supported the military operation in Kosovo against his own pacifist instincts, as well as the allied intervention in Afghanistan. But he drew the line at Iraq, bolstering what some saw as Mr Schröder's opportunism with arguments of exemplary rigour.

As a straight talker, unashamed bon viveur and passionate environmentalist, Joschka Fischer had his contradictions. But strength of character was also the reason voters rallied to his cause, and it should offer a lesson to politicians everywhere. We mean it as a compliment when we say it is probably too early to write his political obituary quite yet.