For many Belgians the events surrounding a referendum held 50 years ago this month broke the final tenuous psychological link that bound this unnatural state together.
The irreconcilable polarisation between Flemish and Walloon that followed, followed as night from day. It was, they say, the point of no return, the day when the ostensible symbol of national unity, the monarchy itself, split the country down the middle.
And yet, need the vote which led to the abdication of the recently returned Leopold III have been so politically devastating? In retrospect it appears as if the Belgian political class dug a hole for itself, and never stopped digging.
On March 12th, 1950, a majority - 57.68 per cent - voted for the restoration of the constitutional powers of Leopold, their disgraced king in exile in Switzerland. But the result was neither good enough, nor poor enough, and, worse still, a comfortable victory in Flanders was mirrored by a defeat in Wallonia, the worst possible result.
By August a wave of strikes and increasingly violent demonstrations made his position untenable and the king stepped aside to allow his 19-year-old son, Baudouin, to assume the powers of regent, and a year later, through formal abdication, the throne itself.
Republican sentiment on the hard left had made common cause with those, largely in the Francophone community, who still felt betrayed by the king's "treachery" during the war.
It had taken all of 18 days in May 1940 for the German army to surround and then extract a surrender from the Belgian army and its king, who made the unfortunate decision not to flee the country. Leopold's choice left him a hostage of the Nazis, and although he refused to administer his country on their behalf, earned him the abiding hatred of a large section of his people.
Rescued by the Americans in 1945, his return to the Belgian throne at that stage was out of the question, and Leopold's powers were assumed as regent by his brother Charles. He went into exile in Switzerland, although a commission of inquiry was to find him not guilty of collaboration.
But the deeply divisive issue of his return would not go away, and in 1950 Parliament took the controversial decision to hold a referendum. The question was simply: "Do you agree that Leopold III should resume the exercise of his constitutional functions?"
It was "folly", the Socialist leader, Paul-Henri Spaak, warned, a recipe for inter-communal division and a wording that enormously favoured the anti-monarchist cause. He argued that the question instead should be "are you for Leopold or Baudoin?" Others warned that the separate tallying of regional votes was bound to emphasise the country's linguistic divisions.
It did, explosively. While Flanders registered over 70 per cent in favour of the king's return, Wallonia and Brussels were opposed, with only one in three in francophone Hainault backing the king.
An uneasy calm descended over the country, a calm that perhaps lulled the new Christian Social government of Jean Duvieusart into allowing Leopold to return from exile in July.
Then all hell broke loose. Demonstrations, strikes, riots. In a town near Liege a group of policemen, isolated by a hostile crowd, fired on them, killing four. Even the moderate Mr Spaak was carried away, warning the Interior Minister: "Unless there is a definitive solution within 36 hours, we will sweep aside your king, his family and hangers-on." Plans were under way for a "march on Brussels".
Mr Duvieusart, whose party was enjoying its first - and last - absolute majority, courtesy largely of its role in defending the monarchy, panicked. In an exhausted attempt to convince the king to resign he would misunderstand the latter's willingness to negotiate a temporary transfer of limited powers to Baudouin. The king would hear to his surprise and anger on the radio that he was about to abdicate.
Too late to stop the rollercoaster and unable to prise supporters from the cabinet to set up an alternative government, Leopold bowed to the inevitable.
And the poison of sectarian division was injected further into the political system. Why, the politicians of Flanders asked, bother voting when Wallonia can overturn our majority will on the streets? Fifty years on and this state is held together by little more than a thread.