Even the modern Bagehot, Professor Vernon Bogdanor, weighed in to declare Mr Cleggs view absurd. The political scientist, Philip Cowley, added that what will determine who gets into No 10 after the election will be the numbers, not bogus arguments about legitimacy. If any leader can command 323 votes in the House of Commons a government can be formed, they said. The mathematics are brutal and unanswerable.
I am about to commit the political equivalent of swearing in church but the distinguished professors Bogdanor and Cowley are wrong about legitimacy, as are all the website seat-projection artists. It is true that any alliance of parties that can command a Commons majority will be legal and constitutionally permitted to do so. It does not follow that such a government would, therefore, be legitimate because, if we take our eyes out of the weeds for a moment, that is not what legitimacy means.
The founding philosopher of political legitimacy is John Locke who wrote, in the Second Treatise, that government is not legitimate unless it is carried on with the consent of the governed. It makes sense to say, for example, that the unelected House of Lords has less legitimacy than the elected Commons. That does not make the Lords unconstitutional.
It is in this context that the Labour party has to consider the outcome being urged upon it by the desiccated calculating machines. Think about a situation in which Labour comes second, both on share of the vote and number of seats won, but can nevertheless, with the support of the third party, the nationalists, the SDLP and George Galloway, gather 330 seats. Enough to govern. Should they then pursue it? Well, in the event they decided not to do so, because those are the 2010 election numbers, if you replace the SNP now with the Liberal Democrats then. Senior Labour people felt at the time, rightly, that they had lost. They felt that a Labour-led government would have been possible but not legitimate.
The question of legitimacy will linger after this election. A prime minister will take office on a low share of a low turnout. A Tory-led coalition will lack legitimacy in Scotland but will at least have the argument that it is led by the party that won most seats and votes. A Labour-led coalition will lack legitimacy in England and, if it is governing from a clear second place, it might be better to seek a second election than to walk first into power and then into oblivion.