Now, as the dust settles in Westminister, Lord Rees-Mogg moves rather nearer to the centre of the stage. Next week the action shifts back to the High Court, which has already given Rees-Mogg leave to proceed with his application. Those who predicted that the erratic cross-bencher would be laughed out of court on day one have already been proved wrong.
Even so, Mr Price's bold assertion almost certainly inflates the importance of a self-publicising, though entertaining and intellectually stimulating intervention by the former editor of the Times. The consensus among constitutional lawyers appears to be that his application is likely to fail. But the high-pitched claim made by Mr Price was typical of the Rees-Mogg style. Here he is, behaving as he believes an Englishman should - conscious of England's history, jealous of its freedoms and impervious to scorn and disbelief.
The self-appointed sage, futurologist, antiquarian bookseller and wholesale collector of public appointments, is not given to self-doubt. He is much committed to and impressed by the importance of the often quirky crusades he undertakes.
On this occasion he has already made an impact and guaranteed himself at least a footnote in the history books. The Government has pledged that it will not ratify the treaty before the courts have reached a final judgment sometime this autumn. And Betty Boothroyd, the Speaker of the House of Commons, has felt compelled to utter a grave warning to the judiciary about the constitutional impropriety of their stepping across the line between courts and Parliament drawn in the Bill of Rights.
Deep waters, indeed. Perhaps, say friends, William - after a lifetime including many spectacular misjudgements that would have led more shrinking men to trim their sails - just could be on to something big. They talk with the hesitation of people who have too often found themselves swept along by Rees-Mogg's off-beat enthusiasms and come to regret their temporary loss of judgement.
For the thing about Baron Rees-Mogg of Hinton Blewitt in the County of Avon is that he can and does get things spectacularly wrong. As a newspaper columnist, which is a part of the way he has earned his living, he is often a powerful, fluent and acute performer with an endless power to infuriate, often riding his hobbyhorses far into the sunset and beyond.
Fortunately for one who is capable of spectacular misjudgements, mistakes do not give him pause. Look, for example, at two of the many columns he wrote for this paper. One was produced in 1988, soon after the Lockerbie bombing, as a result of which 270 died. Rees-Mogg, who had taken Pan Am Flight 103 three weeks earlier, waffled on about the choice of champagne or orange juice and the packet of roasted nuts served in Club Class ('I chose orange juice') before offering his belief that metal fatigue induced by turbulence had caused the crash.
The other was less bizarre but equally perverse. On November 20 1990, the day of the first ballot for the Tory leadership, Rees-Mogg wrote: 'Thatcher has won . . . the victory was clearly a decisive one'. By mid-evening it was apparent that no other political commentator subscribed to this view. Mrs Thatcher had been mortally wounded and every observer knew it. Yet Rees-Mogg made no attempt to revise his copy; in fact, he returned to the fray in subsequent days, never giving an inkling that he had got it wrong.
So why is he taken at least halfway seriously? Partly it is the potency of this English vision of his and an aura that might persuade you that this fogeyish figure has access to wisdom denied to lesser mortals. His family must surely have been around for a thousand years or so, playing an essential role in the constitutional process? Actually, no. His life peerage was granted by Margaret Thatcher only five years ago.
Historically, the Rees-Moggs were neither very grand nor very rich. Nor were they a political family. He was the son of a relatively modest Somerset landowner who married an American actress. 'Squirearchical and quintessentially English - with a dash of something exotic stirred in' according to someone who served with him on the committee of the Oxford Union. William probably viewed them as the sort of family that has been a part of the backbone of the country, a family that might one day contribute something important and noticeable - probably he thought it was him.
He was head boy at Charterhouse, and went up to Balliol as the prestigious Brackenbury Scholar to read history in 1948. 'He swam effortlessly upstream,' says a schoolfriend. 'It was almost as if it was pre-ordained. Even at Charterhouse he knew instinctively how the hierarchies worked.'
The novelist Simon Raven, in his memoir Shadows on the Grass, gives a malicious and very funny account of the ambitious and rather priggish Catholic schoolboy cultivating potentially valuable friends, including the future Lord Prior, and promoting his own, often eccentric, world view. On one occasion, for example, he supposedly spread the rumour that masturbation - a habit widespread among the younger pupils and one which Mogg deplored - caused syphilis.
At Oxford, Rees-Mogg made his mark, but, to his surprise and chagrin, failed to gain the First expected of a Brackenbury Scholar. He got a Second. He was shocked when the classlists were posted. Within minutes he recovered and announced grandly to friends: 'I rather thought the examiners would not like the style of my papers.' According to one who was present as the notice went up, 'It was almost as if the examiners had failed to pass a test set by William.'
He became President of the Union on the Conservative ticket, in a period in which the Union was packed with star performers, including Robin Day, Jeremy Thorpe, Tony Benn and the late Edward Boyle. Oxford is accustomed to ambitious undergraduates polishing their images and cultivating the great and the good. But there was some resentment in Balliol of the deliberation with which Rees-Mogg networked. One evening when he swept into Hall in his long, scholar's gown to dine, the other undergraduates burst out - to the tune of 'Lloyd George Knew My Father' - 'Rees-Mogg knows the Master/The Master knows Rees-Mogg'. (A cruel and unverified addendum to the story has the Master of Balliol asking in puzzlement who this Rees-Mogg was.)
The more cynical of his friends wondered how much Rees-Mogg had done to promote the rumours about the grandeur of his background that somehow spread through the university. He was said to have inherited a fortune and to spend his mornings in bed ringing his stockbroker. In fact, Rees-Mogg inherited pounds 3,000 from an elderly aunt, a tidy sum in those days, but by no means a fortune. And undergraduate rooms did not, and do not, run to telephones.
After Oxford, Rees-Mogg moved directly to the Financial Times, as one of a stable of bright young men recruited by Sir Gordon Newton, the legendary editor who revolutionised the staid publication. Within three years he had become chief leader writer. Between 1960 and 1967, he occupied a number of senior financial and political posts on the Sunday Times before becoming editor of the Times in 1967, a position he held for 14 years.
Those who knew him as a rather buttoned-up journalist nevertheless envied the ease with which he could construct and sustain a written argument, however perverse the initial premise. (He does not type and therefore dictated his leading articles to a secretary. They seldom needed any editing.) But former colleagues also concentrate on his ability to bluff. 'I used to ask myself how on earth he got all that knowledge of economics,' said one non-economist. 'Then I realised he was hustling.'
Authority came easily to him. A former colleague reports an editorial conference at the Sunday Times magazine a quarter of a century ago. The subject was Formula One motor racing - about which Mogg knew nothing - and the role of Enzo Ferrari. 'There was no reason for him to say a word, but Moggie bullshitted like a professional. I have never heard such nonsense spoken with such conviction.'
Another ex-Times man says more kindly that Rees-Mogg had the enthusiasms of an (economically) uneducated man. 'Hard as it may be to believe today, he discovered Europe and for a while saw that as a panacea. He discovered incomes policy and got all excited. He discovered the gold standard and the same thing happened. Peter Jay (then economics editor of the Times) told him about monetarism and he fell for that.'
When Rees-Mogg left the Times in 1981 he took over the antiquarian bookshop Pickering & Chatto, in Pall Mall, joined the board of GEC, and was made vice- chairman of the BBC's Board of Governors and chairman of the Arts Council. It was clear that he had been accepted, in Margaret Thatcher's phrase, as 'one of us'. He was eligible for public service under the new regime. In 1988 came the life peerage.
Rees-Mogg enjoyed his status as an intellectual flagbearer of the new right. And yet he was never quite as close to the former prime minister as it sometimes appeared. He did not sit late into the night sipping whisky at Number 10 and was seldom seen at Chequers. His public appointments, though enviable, were not exactly at the cutting edge of the Thatcherite revolution. A man of his ambition and self-confidence could have hoped to end with something more substantial than the chairmanship of the new Broadcasting Standards Council - a busybody authority with no great clout - which he left last month. The chairmanship of the BBC perhaps? An ambassadorship? Or even a seat in Mrs Thatcher's Cabinet.
Rees-Mogg has stepped apparently effortlessly upward, made himself a pillar of the establishment and gained a succession of glittering prizes. He may feel also that for all these years he has been trying to speak for England. And with that in mind, as well as a showman's flair to carry him forward and James Goldsmith's money to cover the cost, he marches towards the court.