In 1949 Christopher Hollis, a Conservative MP of independent inclinations, published a book entitled Can Parliament Survive? Three years later George Keeton, a professor of law, brought out The Passing of Parliament. Even before I was born, learned works were predicting the imminent demise of that institution. These concentrated less on the coercive powers of the whips than on the legislative powers of ministers, exercised through regulations which were in practice free of any parliamentary scrutiny.
In the 1960s the theory of parliamentary weakness reached a peak which it maintained. It did so because it meshed with the logically separate but apparently congruent theory of prime ministerial (occasionally varied to presidential) government. John Mackintosh's misunderstood British Cabinet and R H S Crossman's Introduction to the Fontana edition of Bagehot's English Constitution played a part in the acceptance of these theories. Indeed, it was Crossman who was principally responsible for the misunderstanding of Mackintosh.
The academics, nearly all of them, swallowed it whole. The only people to put up the slightest resistance were journalists: Ronald Butt in The Power of Parliament, Henry Fairlie in The Life of Politics and myself in a smaller way of business. Sometimes I felt like a voice crying in the wilderness.
Our vindication was the fall of Margaret Thatcher in 1990. True, she was not deposed by a vote in the House but, in practice, by a vote of the government backbenchers. This was then confirmed by her cabinet. She blamed the cabinet. Even so, both theories - of backbench ineffectiveness and cabinet docility - were killed with one stone.
The reign of Mr John Major did nothing to revive the previous view of the constitution. How could it? He was, according to his friends, a collegiate prime minister and, according to those who thought less well of him, an ineffectual one. In any case, his majority was falling as James Callaghan's had in 1976-79: there were periods during his term of office when the government might have fallen. In one of these spells, connected (as they all tended to be connected) with the Maastricht treaty, the whips, acting presumably with the authority of Mr Major, threatened a general election. "We wouldn't have let him get halfway down the Mall," one of his colleagues commented at the time, so reviving the pre-1914 doctrine that the authority for an appeal to the people (as distinct from the channel to the sovereign) was the cabinet and not the prime minister.
In May 1997 all was changed, Mr Tony Blair a commanding figure with a huge majority. Both factors, Mr Blair's majority and Mr Blair's personality, have led naturally to a revival of the theories of prime ministerial power and parliamentary ineffectiveness.
Over welfare reform the revived theories have not worked. This is largely because Mr Blair does not know what to do about welfare. He is more a Harold Wilson than a Margaret Thatcher. No one knows what to do, certainly not Mr Alistair Darling, the plausible Scots lawyer who took over from the luckless English lawyer Ms Harriet Harman. Not even that other discarded minister, the saintly Mr Frank Field, knows what to do, though that did not prevent him from voting against the Government last week.
Mr Field believes that everyone should be forced or, at any rate, encouraged to make private provision for his or her old age. This is all very well, disregarding as it does the fly-by-night character of many of these private pension providers ("Kindly sign this piece of paper, my dear sir, a mere formality I assure you, while I put on my running-shoes"). But even in a less sinful world, the fundamental difficulty would remain: why is one benefit means tested, and the other not?
Mr Darling was asked about this on television. Why were family allowances not means tested? Just so, the slippery fellow replied, repeating the question as an answer: family allowances were indeed not means tested. But why? Answer came there none.
By contrast, it is laudable to save for your old age precisely because the government will not have to help you, or will do so on a diminished scale: though it will continue to assist if you have been imprudent during your working life. Save for a rainy day! Well, the rainy day is here, old lad, so you can fork out: that is the message of the Conservative Party and of New Labour alike.
But over Yugoslavia the theories of prime ministerial power and parliamentary ineffectiveness have worked - so far. Partly this is because we are, however unwisely and indeed illegally, fighting a war. The Labour Party has been docile, with the Left split, and the Conservative Party ineffectual, with Mr William Hague trying to follow public opinion with all the delicacy of Peter Sellers as Clouseau stalking a criminal in darkest Montmartre.
It is not true that oppositions always support governments over wars. It has not been true even in the post-1945 period. Hugh Gaitskell and Labour opposed Anthony Eden's Suez adventure, though it is still a matter of argument among historians about whether he changed his mind after offering Eden his initial support. What is not argued about, because no one seems to have noticed, is whether Michael Foot behaved similarly towards Margaret Thatcher over the Falklands. In that first emergency debate he was undoubtedly in favour of decisive military action. As the conflict progressed, however, he attacked her for bypassing the United Nations and, in particular, for not treating more seriously the "Peruvian terms". Denis Healey was more pacific still.
What Mrs Margaret Beckett says is also untrue: that it has "long been the tradition of the House" that, once British troops are engaged in conflict, no substantive motion is allowed which "might cast doubt on our support for our troops". She was corrected by Sir Peter Tapsell, citing the Maurice munitions debate in the First World War and the Wardlaw-Milne motion of censure on Winston Churchill in the Second.
Sir Peter might have added that Neville Chamberlain fell and was succeeded by Churchill after an inadequate though winning vote on the motion for the adjournment. On that occasion a motion of censure was first considered but then rejected for reasons of political tactics - that it would attract support for Chamberlain - rather than of constitutional impropriety.
Parliament has been dying for a long time. Then, just as the Co-op chapel of rest has been booked for the body and the ham has been ordered for the sandwiches, it sits up in bed and asks for a cup of tea. This is what it did last week over the invalids' benefit. It is what it may yet do over the bombing of Yugoslavia. This outcome will require some political courage on the part not only of government backbenchers but of Mr Hague. So far this has not been forthcoming.