"Warmongers! warmongers!", chanted the protesters as Green Party delegates, escorted by police, made their way into Bielefeld's Seidensticker Hall. It was May 13, 1999, and the children of May 1968 had an appointment with reality.
Over the rogue state of Serbia, Nato bombers were staging a "humanitarian intervention" on behalf of the threatened citizens of the breakaway province of Kosovo. For the first time since the end of World War II, German forces were engaged abroad.
Joschka Fischer, Green Party leader and foreign minister in Germany's first red-green coalition government, had endorsed the decision to intervene. At Bielefeld, 800 delegates would decide whether his dramatic departure from the Green Party's founding principle of "non-violence" would stand. The long-simmering battle between the Right-leaning "realos" (realists) and the Left-leaning "fundis" (fundamentalists) was about to be decided.
As it usually does, "reality" won the day at Bielefeld. The German Greens, faced with the choice of modifying their principles or stepping away from their coalition with the Social Democrats, decided (415-335) to modify their principles. All violence might be awful - but some forms were more awful than others.
The Nato sorties continued.
Whether they believe the German Greens grew up - or sold out - at Bielefeld, New Zealand's Greens, at some point during the next three years, will inevitably be faced with a Bielefeld of their own.
It is entirely unrealistic for a political party to join a coalition government without first acknowledging the inevitability of compromise. This is especially true if the party in question attracted fewer votes, and thus has fewer seats, than its prospective partner. The larger party cannot be expected to re-order its policy priorities or sacrifice its leading personnel merely to keep its junior partner happy. To do so would attract - and merit - universal scorn.
Such are the brutal realities of coalition politics. Parties either accept them - and become genuine players in the political game. Or, they reject them and remain permanent political spectators.
It is really only the world's Green parties that struggle to accept these largely self-evident rules. As the ideological offspring of May 1968 (when the great counter-cultural uprising of the world's youth reached its zenith), the prototypical German Greens eschewed all political hierarchy in favour of "appropriate decision-making" - by which they meant "grass-roots", "bottom-up", consensus-based democracy. And this was no mere rhetorical flourish: Greens really do believe that the way they arrive at major decisions is every bit as important as the decisions they make.
All of which lays a heavy burden on the shoulders of Russel Norman and Metiria Turei. Rather than laying claim to portfolios that their prospective coalition partners in the Labour Party couldn't possibly agree to assign them (not without opening up huge divisions within its own ranks), the Greens co-leaders should be thinking about how to reconcile their fellow party members to the unavoidable compromises of coalition politics.
Because these are likely to be both numerous and unpalatable. On practically every economic and social issue that matters, the Greens have positioned themselves well to the left of Labour. That being the case, very few, if any, of the Greens' preferred solutions to the high dollar, unemployment, child poverty, homelessness, climate change and dirty dairying will win Labour's unqualified endorsement.
As a political party on its way to the treasury benches, the New Zealand Greens would be wise to learn from the experience of their German counterparts. Tumultuous gatherings on the model of the Bielefeld conference make for the most stunning political theatre, but the long-term consequences in terms of preserving ideological coherence, or even the enduring goodwill and commitment of the party rank-and-file can be extremely debilitating.
It wasn't just an earful of red-paint that the "warmonger" Joschka Fischer received in the Seidensticker Hall. His role in undermining the Green's pacifist traditions won him a new and much-less-flattering image than the "principled activist" persona he had worn since 1968.
Reality plays no favourites.