As they have long meditated on the virtues of a united continent ("Trans Europe Express", "Europe Endless"), "no" votes in France and the Netherlands must make these trying times for Kraftwerk. Yet there were no sign of distress as they proved that the most elegant electronica can work in a live environment.
This tour continues a period of massive activity, relatively speaking, that began in 2003 when the cycling fans from Düsseldorf marked the centenary of the sport's most famous contest with Tour de France Soundtracks, their first original work for 17 years. Now they are on the second leg of a rare world tour, marked this month with a live album, Minimum - Maximum.
Of course, the key challenge for Kraftwerk is how to add excitement to blokes pressing buttons on laptops. They answered this with a dismissive "so what?" as they lined up side by side in identical business suits behind their tiny screens on thin-legged tables. For the next two hours, they spoke not a word and barely moved, apart from a stiff-backed wiggle from the founder member Ralf Hutter and Fritz Hilpert's puppet-string jerks.
They were faced by 7,000 Serbians packed into a decrepit, graffiti-strewn amphitheatre. A young, boisterous crowd greeted with enthusiasm a static performance augmented by a light-show that bathed the quartet in different mood-enhancing hues for each number and mammoth screen projections behind the stage.
The venue's oval bowl was a perfect space for Kraftwerk's visions of utopia. With unnerving precision, the band filled out the stark, timeless melodies of their best-loved tunes. On "Tour de France", digitised breathing provided a rumbling bass pulse that augmented its delicate rhythms. "The Model" came with a slightly faster tempo. That tune's nerdy charm was surpassed by the yearning "Neon Lights".
"Radioactivity", their ode to the benefits of communication, began with a warning about leaks at Sellafield, before Hutter introduced anti-nuclear lyrics based around the now ironic refrain, "It's in the air for you and me". The stark melody became a harbinger of impending doom, until its "Blue Monday"-style click rhythm gave the crowd leave to dance once again.
More dry humour was revealed in the encores. First, they arrived in diode-lit ties. Then came the band's android doppelgängers for "Robots", greeted with cheers as raucous as for the real thing. Finally, the four-piece returned in suits with glowing lines that created an effect similar to the early virtual reality film Tron.
Still you could not tell what each member contributed to the performance, if anything at all, until they took turns to provide their own brief solos of slightly increased complexity before they bowed and left. Last man standing, Hutter offered a tentative thank you and farewell.
Touring to 7 July