But what if it ain't so? What if "will" is really "may"? The last time a Liberal prime minister evacuated No 10, perhaps he too thought, "We'll be back", before adjusting his monocle and climbing into the back of the Daimler. Seventy years on, his successors are still waiting. So there is nothing inevitable about political revival, and nothing immutable about two-party alternation. If there were, all the Tories would have to do is wait.
Let us assume, for a moment, that the Tories would regard the 18 years out of power just experienced by Labour as being a disaster of unprecedented magnitude. Since the Second World War, the longest period of opposition the Conservatives have had to endure was from October 1964 to June 1970. The experience of defeat in 1974 was sufficient to provoke a massive ideological re-evaluation; the defeat of the leader in an election, the junking of the post-war consensus and the advent of what later became Thatcherism. So the historical evidence is that the Tories won't simply sit around deciding whether or not to wear ties.
But where is the Sir Keith Joseph of 1999, where the millennial Milton Friedman? What great brains strain, in what foundations, to provide a renewed party with a clear sense of purpose? Where are the new ideas upon which a renascent Toryism can build? As football fans sometimes chant at the supporters of teams losing six-nil: "It's all gone quiet over there."
In my youth I used to enjoy using the word "hegemonic". As Thatcher flattened all before her, and the left contemplated its ruin, "hegemonic" seemed to describe well the intellectual and practical hold that free-market notions appeared to exercise over public discussion. This hold wasn't enforced by the Army (as in Chile), or by "false consciousness" on the part of those skilled workers who voted for her, but by the lack of a coherent alternative story.
After Mr Brown's Budget, the Third Way seems also to be hegemonic. It accepts capitalism, and promises to modify it in the name of social justice. It harnesses the private in the service of the public - instead of emphasising the tension between the two, or seeking the victory of one over the other. If it is rather nebulous, that suits an age that shuns easy solutions. Above all it seems to be inclusive, rather than delighting - as most ideologies do - in who cannot enter the Promised Land. Round the kitchen table (upon whose homely surface Mr Hague says he wishes to dance), Middle England follows Tony. So there are huge problems for anyone who seeks to find an alternative to this updated form of social democracy. The Liberal Democrats, for example, are Third Wayers, differing only in matters of detail - despite Malcolm Bruce's ingenious way with income tax.
In a reformed electoral system, there might be ideological space for a genuinely socially libertarian entity on the right, just as there would be room for an aggressively redistributionist or environmental party on the left. But neither would be able to command sufficient support from the electorate to rule on its own.
This leaves two big possibilities for a party of opposition. The first is to promise to manage the Third Way more effectively than Mr Blair and his lot. The second is a return to a wholesale and unashamed advocacy of free-market economics.
But which does Mr Hague favour? His visit to Texas last month did not clarify things; there is not much to be learnt there, except how to ride a rodeo horse. The only great political virtue of the Texas Governor and Republican presidential contender George W Bush is that he is neither Dan Quayle nor Pat Buchanan. The brand of "caring conservatism" that Mr Bush favours is so called because it isn't a prisoner of the Christian right, and doesn't call for gay people to be castrated, or for abortion clinics to be closed down wholesale. It's not of much help when trying to decide whether and how the state should care for the poor.
In Britain, the Daily Mail largely fulfils the role played by the Christian right. And even here, despite its lack of battalions, it seems to prevent any great move by the Tories towards a social liberalism. One moment we are told that the Conservatives are inclusive and compassionate; the next moment we have the knee-jerk extolling of marriage over all other forms of cohabitation.
In addition, where Mr Kinnock, say, fought off the far left in order to shift Labour back to the middle ground, William Hague embraces his ultras on the one issue that matters to them: Europe. Even worse has been the association of the Conservative Party with just about every unpopular vested interest in the country, including - this week - the Country Landowners' Association's opposition to a right of access.
This confusion is even worse when you consider the Tory stance on taxation and expenditure. Kitchen-table Toryism speaks softly to teachers, to parents and to health workers. On Monday, Michael Portillo lamented the desertion of the party by public sector workers. "I think one of the things an opposition can do," he said, "is associate itself with the grievances people are bound to have - and, let's face it, there are still teachers worried about conditions and standards in school, and nurses worried about their value and whether they are paid enough."
But six weeks ago Mr Hague stated that "spending [is] higher than it should be, and taxes [are] higher than they should be". How then are disaffected teachers and nurses to have any hope in a resurgent Conservatism? And if the answer is that the Tories will indeed be looking to use the power of government to ensure more equitable social outcomes, how is that to be squared with the recent commitment to "set our entrepreneurial spirit free from the dead hand of the state"?
It isn't. Mr Hague is stalling because he does not know which strategy he wishes to embrace. No Neil Kinnock has gone before him to lay the path, no Mandelson to crush the gravel. The think-tanks are empty.
At the end of January, in his speech to the Scottish Tories, William Hague concluded with this sentence: "We have started to change the Conservative Party," he said; "now we must make sure we finish it."
Perhaps he will.