Gordon Brown should have done it at the beginning of the recession. He and David Cameron should be thinking very seriously about it now. Perhaps national government is an idea whose time has come. Again. With the prospect of a very close election, in which people are clearly sick of the conventional two-party system, there is every reason to imagine a genuine government of all the talents after the election, with ministerial posts given to senior figures from all three parties.
Is there any reason that Nick Clegg shouldn't be prime minister in a national government? It would seem he is the people's choice.
The obvious objection is that a national government would be anti-democratic. But it would be no less democratic than a government led by a man who hasn't even been elected as the leader of his own party.
I recognise, however, that such an arrangement would have to be temporary. But I think it is possible to argue that this election is likely to act as an argument for significant political change, whoever wins it.
A national government could be the precursor to a new political settlement, including electoral reform.