"Social democrats of the world unite" just doesn't have the same ring as the old exhortation to the workers.
It seemed appropriate that the auditorium where 1,200 delegates from 143 countries met yesterday for the Socialist International's last congress of the 20th century should be located beneath a shopping centre. They didn't even sing The Red Flag.
And while Mr Lionel Jospin and Mr Gerhard Schroder addressed their "dear comrades", Mr Tony Blair simply called the representatives of the world's socialist, social democratic and labour parties "my friends".
With 11 of the EU's 15 nations governed by socialists, with leaders from the former east bloc active participants and the ruling South African ANC a new member, socialism has never been so powerful. Even Uncle Sam's back yard is going socialist. Speakers congratulated Argentina's president-elect, Mr Fernando de la Rua, and encouraged socialists who are on the verge of winning elections in Uruguay and Chile.
Many of the congress's older delegates were once in Soviet-backed "revolutionary" movements from the developing world. Without changing their names or leaving the Socialist International, they have now joined the global establishment. But if, as the French Prime Minister, Mr Jospin, said, socialism is no longer a system or a doctrine, then what is it?
At the apogee of its appeal, socialism has never been so ill defined. A quick comparison of the "Paris Declaration", the painstakingly negotiated 14-page text issued last night, and a 1908 speech by the early French socialist Jean Jaures shows how much socialism has changed.
Jaures talked about solidarity between classes, workers' power and trade unionism. Yesterday's declaration advocates fighting poverty and hunger, campaigning for human rights and democracy and establishing peace and security.
But the pious sentiments did not hide the animosity between the British and French prime ministers. Mr Blair enraged French socialists last year by proposing an alternative to the Socialist International that would have linked his New Labour with the US Democratic party and Italian socialists.
When that didn't work, Mr Peter Mandelson (before he became Northern Ireland Secretary) and Mr Bodo Hombach, one of Mr Schroder's top advisers, hammered out the June 1999 "Blair-Schroder Manifesto". Mr Jospin never forgave Mr Mandelson for calling him a "dinosaur" two years ago. "I don't mind theory," Mr Jospin said when confronted with the manifesto, "but I don't like being told what to do."
Because of the ideological warfare between "social liberal" Blairists and orthodox Jospinists, the Paris Declaration contains no reference to "the flexibility of markets" which the Blair-Schroder manifesto called "an objective of modern social democracy".
To their satisfaction, the French managed to slip in a reference to socialism's "critical attitude towards capitalism". On the eve of the congress, Mr Blair retaliated by addressing a letter directly to the French people through the Journal du Dimanche, warning socialists against being "the immobile guardians of outdated dogmas".
So when Mr Blair straggled on to the stage like a tardy schoolboy an hour and 20 minutes after the congress opened yesterday morning, Mr Jospin did not greet him or even look at him. Mr Jospin's speech was historical and political, while Mr Blair's centred on enterprise and the challenge of new technologies.
This is not the first time technology has changed our lives, Mr Jospin said, comparing the advent of the information age to that of electricity, the telephone and air travel. Mr Blair was much more emphatic, alluding to "technology that means our children's lives are already light years away from our own youth".
Europe's third "heavyweight" socialist, Mr Schroder, was in a hurry to get back to Berlin to celebrate the 10th anniversary of the dismantling of the Wall. Having been burned at the polls by his flirtation with Mr Blair, the German Chancellor has receded from the Blair-Jospin fray, and he preferred to talk about the mistakes of German conservatives yesterday.
For all his alleged old-fashionedness, it was Mr Jospin who definitively buried the centrally planned economy, along with the socialists' communist cousins, whose ideology, he said, became "a murderous perversion of a sincere idea, and ended up in a totalitarian system".
Socialism, he said, "no longer exists as a system, and to start with, as a system of production". The market was clearly superior to central planning in creating wealth and allocating resources, Mr Jospin admitted. But the market must be regulated. "In itself, the market creates neither meaning, nor direction, nor a plan."
The "gut instinct of the old left" was to resist change, Mr Blair argued, but if it failed to adapt, the left would actually cause injustice. By "old left", he clearly meant Mr Jospin.