It is a mistake to see last week’s ugly demonstration of Brussels-style arm-twisting, chicanery and treachery as a humiliation for David Cameron.
If anything, it is German Chancellor Angela Merkel whose fabled reputation for soft but deadly diplomacy is in tatters, with serious questions over her integrity.
But it is the European Union itself that emerges at its shabbiest, treacherous worst.
The brutal imposition of drunken Jean-Claude Juncker as President of Europe against the wishes of one of its largest member states has changed everything.
Uninvited, the iron has entered David Cameron’s soul. Having vowed he would not be the Prime Minister to lead Britain out of Europe, he must now put the nuclear option back on the table.
I am told Mr Cameron will signal shortly that — without real EU reform on immigration and other key demands — he will indeed lead an OUT campaign in Britain’s 2017 referendum.
Since he is unlikely to wring those concessions out of a bruised and vengeful Juncker, the clock on Britain’s membership is already ticking.
This is an uncomfortable position for Mr Cameron. But Merkel has left him no choice.
She promised to help block Juncker, then caved in under domestic pressure and left the PM looking foolish.
He cannot trust her again. Nor will his Tory MPs let him. Friday’s disastrous summit vividly exposed Brussels’ trademark horse-trading, arm-twisting and double-dealing.
It is now possible to imagine Britain leaving the European Union, threatening its existence as an undemocratic and unaccountable socialist experiment.