You have to hand it to William Hague. Early in the election campaign, the then shadow Foreign Secretary sat in the back of David Cameron's bus and mused calmly to a couple of reporters about what he implied might well be, if it came to it, an achievable accord between the Conservatives and the Liberal Democrats.
Although it was the day after Nick Clegg had shot to prominence in the TV debate, it was startling indeed to hear a senior Conservative, even one with as much historical knowledge as Mr Hague, think aloud about what then still seemed the utterly outlandish prospect of the first peacetime Lib-Con coalition for 70 years.
In fact, of course, he read it exactly right. This didn't mean it was inevitable, much as it may seem so given the smoothness and evidently genuine cordiality with which the two leaders have ushered it in. A Lib-Lab arrangement was indeed possible. Stanley Baldwin, as Mr Hague will know better than most, came first in seats and popular vote in the December 1923 election, but was obliged to recommend the following month that George V send for Ramsay MacDonald, when it became clear that the Liberals under Herbert Asquith were not going to let his King's Speech through parliament.
What Mr Hague appeared to guess correctly, however, was that Asquith's distant successor would see his destiny – in admittedly different times and circumstances – otherwise. If he also guessed that David Cameron would go so far as to offer a referendum on electoral reform, he was certainly not letting on. But it was almost certainly a necessary condition for constructing the overall majority the electorate had denied him.
Yet elsewhere the price paid by Mr Cameron has not been that severe. On Europe, he did not have to compromise. And on managing the fragile recovery the Lib Dems have conceded what they argued against in the election, namely that cuts of £6bn are preferable to a rise in national insurance. Indeed, had Mr Clegg wanted to turn to Labour he could have cited this – fairly fundamental – difference as the reason.
But Labour has to deal with what is. It can't rule out the possibility that the coalition, which has undoubtedly started well, suggesting that Mr Cameron is a seriously good manager, is built to last the full course, and even that it may be popular enough to win a second term, perhaps but not necessarily for the Conservatives alone.
But there may be real opportunities for Labour too, and not only because of the likely unpopularity of some of the measures the Government will have to take. Even if there are not destructive splits in the coalition – which by their nature are more likely to become public if they are between rather than within parties – Labour has a better chance than at any time since the 1960s to reconstitute itself as the main and possibly only force on the – hopefully liberal – centre left.
Cameron and Clegg are thoroughly modern, 21st-century politicians, which is an advantage that has to be matched by Labour's new leader. The new Labour leader will have to be in tune with the zeitgeist, pluralist, not tribal, nor locked in his party's past recent or otherwise, nor dependent on one sectional interest of the party. He will need to be very clever to deal with a Prime Minister whose Oxford tutor Vernon Bogdanor described as one of the cleverest students he ever taught. He will need to be good on television and have a touch with "ordinary" people. And he will need to be strategic.
He will need, also in the tune of the times, to be sufficiently driven by a passion for policy to pick the issues on which to oppose the Government and on which to construct an alternative appeal. And it would be an added bonus – given the overwhelming bias in the Cabinet towards those from the 7 per cent of the population educated in private schools – if he had gone to a state comprehensive. And he will need to be a candidate of change – of party as well as of the country.
It isn't exactly original to suggest that David Miliband looks like the candidate most likely to combine all these qualities, given his position – so far – as the bookies' favourite, and the fact that another highly plausible potential rival, Alan Johnson, has decided to back him. And if he can rise – and he has a good chance of doing so – beyond the deforming labels of Blairite and Brownite, he has a real chance of appealing to the widest range of electors, including Liberal Democrat supporters who may become disillusioned with their party's role in government. Even if the labels weren't also obsolete, Mr Miliband, the man Gordon Brown appointed as Foreign Secretary, is rather far from the Blairite clone his detractors may try to make him out to be.
It was after all – to take a few random examples – John Smith who appointed him as secretary of the Social Justice Commission, which laid the basis for a welfare system designed to get people back to work. He is probably several notches to the left of Blair himself. As schools minister he negotiated a path-breaking agreement which brought 250,000 teachers' assistants into schools with the assent of the teaching unions – an almost European-style form of social partnership. Indeed, he is a true social democrat in the sense of the term before it was "polluted" – as he himself has been heard to lament – by the SDP. And he was the sole minister to urge Tony Blair – correctly – to call for a ceasefire in the 2006 Lebanon war.
That said, the way the party conducts the leadership contest may be almost as important as who wins. A genuine debate of ideas has to be carried out in a spirit of fraternity (literally if Ed Miliband stands) that has been absent in the party's not so distant past. Labour may have to be patient. But it also has to be ready.