There was a time in Labour circles when to be pro-European was regarded as A Good Thing. Actually, it was more than that. Being pro-European was something that those ambitious, clever, upwardly mobile people in the party were proud to call themselves. It was a sign of both moderation and modernisation. Not any more it seems.

Pure naked opportunism mostly explains last night’s decision to side with Tory ultras in calls to cut Britain’s EU budget contribution. Europe is a fantastic inter-party wedge issue for dividing the coalition, but it's catnip for stoking intra-party tension among Conservatives. On the specific issue of curbing the budget, it also, helpfully, gives Labour something concrete to say about cuts.

But this creeping euroscepticism in Labour’s ranks is also partly informed by experience in office. The enduring, lofty ideal of Europe is tempered by seeing the often sclerotic decision-making and undeniable waste up close. As shadow foreign secretary Douglas Alexander declared this morning: "Europe must learn to do better with less and that is why we voted for a real terms cut." The party’s once self-confident and numerous pro-Europeans are quiescent these days. Lions in winter, with neither grassroots support or much interest coming from the leadership.

The trade unions, once hostile towards the EC for being a "capitalist club", changed their tune in the late 1980s when the commission stated getting interested in social policy and workplace rights and proved instrumental in warming Labour’s attitude to Europe. But that was then. Now, the unions are narrowly focused on holding what they have amid domestic spending cuts. Europe can whistle.

At the top of the party there are no real evangelicals for Europe any more. Ed Balls is famously the architect of the five economic tests, wielded as a crucifix to repel any prospect of Britain joining the euro. Policy review head Jon Cruddas has called for an immediate referendum on EU withdrawal, while Ed Miliband didn’t mention the EU once in his recent party conference speech.

Instinctive pro-Europeans in the party like Denis MacShane now seem like curiosities from another age. Especially when compared to former comrades-in-arms like Gisela Stuart, who now believes Britain should actually quit the EU. There is also, perhaps, a generational shift occurring in the party, away from a post-war class which instinctively saw the European project as a force for good in the world and a bulwark against further conflict, and towards younger Labour politicians who take a far more pragmatic view of Europe.

Part of the EU problem is that it has always been a strategic geo-political partnership, not a popular movement. As former SDLP leader John Hume once put it, the EU is the longest-running peace process in the world. But it is not enough for diplomats, bureaucrats and the Westminster cognoscenti to "get" Europe when so many of the public do not. Europe has always failed to find a popular message and populist messengers. After last night, that challenge is now even harder.