Bernard Ingham: This untidy marriage of convenience will go on, despite its disagreements

HOW'S this for a festive cracker conundrum: what's the difference between a coalition and a conventional government? Answer: a coalition has two or more parties; a conventional government just one. Otherwise, you wouldn't notice the difference.

Harold Wilson wore himself out trying to hold his fissiparous government together. I can personally testify that Margaret Thatcher's three administrations over 11 years were hotbeds of intrigue. One Northern Ireland Minister even called her a "cow", though not to her face.

John Major complained of the "bastards" in his senior ranks. And Tony Blair and Gordon Brown waged guerrilla war with each other for a decade – and can't stop. Just like the Montagues and Capulets, minus Juliet.

Let us not, therefore, read too much into Vincent Cable's now defused nuclear option of resignation. Nor Norman Baker, a Transport Minister, who is not resigning, comparing himself to Helen Suzman fighting the South African apartheid regime. Nor Paul Burstow (Paul Who? in charge of Care) and Andrew Stunell (Local Government) who don't trust David Cameron. So what's new?

I suppose the honest answer is that only Liberal Democrats, still marvelling at their Ministerial boxes and limos, would be inclined to open their innermost thoughts to two attractive women sent to trap them with malice aforethought by the now feral Daily Telegraph.

Disgruntled Tories are almost certainly right: any Conservative Minister caught being so threatening or critical, as distinct from wayward like Kenneth Clarke, would have been summarily chopped.

But this is where we come to the real difference between a coalition and a one-party government. One is a marriage of convenience rather than a convenient marriage of more or less similar dispositions. As such, convenience dictates that the coalition will go on and on, with silly Ministers like Cable shorn of bits of their empires they simply cannot administer because of their indiscretions.

After all, nobody wants an election, least of all the comprehensively bankrupt Labour Party. Who would trust them with an economy again this side of the next Preston Guild?

Most people recognise that some tough medicine is necessary and that, since it has to be administered, fervently hope the Con-Dem coalition's prescription works. Indeed, the only serious argument seems to be over the pace at which we are forced to purge our debt.

Cameron towers above any potential Prime Minister. People are revising their dismissive views about George Osborne being a lad on a man's errand. And Nick Clegg, worn though he may be by holding his lot together, has acquired in seven months some of the qualities of a statesman who knows his patriotic duty.

It is, of course, possible that things will go horribly wrong with the economy in the New Year, but I doubt it. Liberal Democrats may be encouraged to get uppity by their nonentity of a deputy leader, Simon Hughes, especially if they do not get their way in the electoral reform referendum.

European excesses, like the Lib Dems' inherent wetness on social issues, are sent to try the coalition.

But let us never forget that, whatever jaundiced views we may have of politicians, Conservative and Liberal Democrats came together last May not opportunistically but out of a sense of national duty. That duty will not have been discharged until Britain is reasonably solvent again. We have a long way to go before we get out of the red.

When that happy day dawns, expect Cameron to propel a Cable clone – or Cable himself if he repeats his mistake – out of Whitehall like a rocket on a moon mission.

All bets will then be off unless, of course, the pragmatic in both parties decide their future is a right-of-centre coalition. I would not put it past a lot of them since hovering around the centre is preferable to them to pandering to the Tory Right and the LD Left.

Much will depend on Tory and Lib Dem calculations of where their party interests lie once they have done their national duty.

However, I cannot bring myself to believe – certainly not yet awhile – that the Liberal Democrats will find a left-of-centre coalition with Ed Miliband's Labour Party irresistible. Miliband does not seem to have an original thought in his head.

After our novel experience of coalition, his evident weakness will influence the shape of Britain's politics for years to come.

Trust the unions who elected him to get it wrong. And on that ironic note, a Happy New Year to you all. We'll still have this untidy, rumbling but ambitious coalition come next Christmas.