"Imagine there's no countries," John Lennon first famously intoned back in 1971. "Nothing to kill or die for. And no religion too."
Religion has indeed often been at the centre of some of the world's worst conflicts. You don't expect anything similar to rage in school classrooms, but that is what is happening throughout Berlin, where prominent members of both Catholic and Protestant churches have staged a passionate campaign to make religious education a compulsory subject in the city state's schools.
It all started in 2006 when the authorities introduced reforms making RE an optional extra in state secondaries; ethics classes were to be compulsory. The argument was the city's schools, with their high proportion of pupils from migrant backgrounds, would fare better if everyone attended the same ethics classes, where common values and intercultural and religious issues could be examined and discussed by pupils as a whole. Indeed, many might say this is no bad thing for Berlin, a volatile melting pot whose inner-city schools have seen violent rioting in recent years.
But the churches bristled at what they regarded as a deliberate demotion of the traditional status of RE. In virtually all other German states, pupils must opt for either Catholic or Protestant RE or attend ethics classes. Church worthies feared that secondary pupils in Berlin, busy studying for intermediate or higher school-leaving certificates, would not bother signing up for RE classes if it became an extra subject. Even worse, young people might ultimately leave the church altogether, and their much-needed ecclesiastical taxes with them.
Hence a decision by prominent Catholic and Protestant church representatives, backed by parents and other supporters, to initiate the Pro Reli campaign in a bid to gather the 170,000 signatures necessary to force Berlin's education authorities to hold a referendum on the issue.
To the triumphant satisfaction of all those involved, the campaign attracted widespread support, generating 307,000 signatures.
Yet, perhaps the most remarkable aspect of the campaign is the fact that both Jewish and Muslim groups in Berlin spoke out in its favour, emphasising their conviction that religion was being done down by city officialdom. This is astonishing indeed since neither Jewish nor Muslim communities are directly affected by the absence of - predominantly Christian - RE in Berlin.
Now the campaigners, flushed with success, are hoping to negotiate a new status for the subject without actually having to resort to a referendum, since any change to the existing education laws would require 609,000 Berliners to vote "yes".
For their part, the city authorities are bracing themselves for a tough fight since figures also show that around 25 per cent of the Berlin electorate would like to see RE made compulsory not just in secondaries, but in primary schools as well. These Berlin-style "religious wars" will be waged for some time to come - although it is heartening to see the unity between the Christian churches and Muslim and Jewish faithful.