Brexit is a huge legal and political convulsion for a European Union which is already struggling to cope with its many crises, deep structural flaws and collapsing political leadership. But the European Council, which meets on Tuesday, should not use the pretext of Brexit to cloak itself in yet more Eurosceptical garb.
The fact is that the referendum campaign barely touched on matters germane to the future of the Europe - a question which most British voters, consumed by domestic troubles, find deeply uninteresting.
It would be foolish to look to Britain to draw serious ideas for EU 'reform'. A country that has just lunged to the radical right is not a good example for the European liberal project.
As for David Cameron, he built his career by pouring contempt on EU institutions; as Prime Minister he has been an entirely negative influence in EU counsels; as the lead campaigner for Remain he was wholly implausible; and soon, unlamented, he will be gone.
Unreliable to the last, Cameron has reneged on his promise to trigger Article 50 at the 28-29 June meeting, leaving it up to his successor in October. Yet the leaders of EU 27 should push for the earliest possible conclusion of the formal Brexit process.
Today's joint statement by Tusk, Schulz, Rutte and Juncker strikes the right note, making it clear that the UK cannot expect any new ‘renegotiation’, and that the Article 50 exercise should be launched promptly.
Delaying the painful business merely to serve Tory party interests would pose an intolerable risk to financial and political stability across Europe: the markets are already in a punitive mood.
Article 50 is designed to achieve an expedient and orderly secession. The withdrawal agreement should be limited to legacy matters, such as the maintenance of acquired rights, which are complex but fairly technical.
The new trading and immigration relationship between the UK and EU 27 will take longer to work out - not least because the victorious Brexiteers have yet to agree on what it is they really want.
The disintegration of the European Union should induce a much sharper debate between those who are willing to reform the EU's finances and deepen the fiscal integration of the eurozone on the one hand, and those who prefer to prevaricate, on the other.
In the first camp one hopes to find European Commission President Jean-Claude Juncker, European Central Bank President Mario Draghi and the European Parliament; in the second one sees European Council President Donald Tusk and Eurogroup President Jeroen Dijsselbloem. It's time to take sides.
European Parliament President Martin Schulz should convene a special session of the Parliament for Tuesday morning, and send an incisive message to the 27 heads of government and to the wider, anxious world.