Sean O'Grady: A neat sidestep of an age-old dilemma, but only if Labour lose

At first sight, Nick Clegg has devised a neat way of avoiding the tricky question that has trapped Liberal leaders from Asquith to Ashdown – "whom do you prefer?" – by simply bouncing the question back to the electorate.

It also recognises the reality that the Liberal Democrats are unlikely to be in the luxurious position of "kingmakers", where they can choose between the two parties. The psephologists say that such a result is freakish, given the vagaries of our first-past-the-post system. There are also the Scots and Welsh nationalists and the Ulster parties, who might also be able to put one or other of the main parties in.

So it's much more likely that any choice Clegg has will be obvious, and he has cleverly made the most of this reality. It also gives him a handy argument to use against the party's viscerally anti-Tory activists if he does find himself attracted to a deal with David Cameron – an appeal to patriotism and the apparent "will of the people" to deal with an economic crisis.

It all goes horribly wrong, though, if Gordon Brown, or some replacement, manages to squeak it and win the most seats. Then we would have the unhappy spectacle of Clegg being obliged by his own pledge to prop up a Labour government which has clearly lost its moral right to govern.

This is more likely than it looks because the electoral system is so heavily weighted in Labour's favour – Labour could easily win fewer votes and still have many more parliamentary seats. The "winning party" in the Commons also polled fewer votes in the country after the 1951 and February 1974 elections. It is ironic indeed that Nick Clegg, the leader of a party that dedicates itself to the destruction of the first-past-the-post system, appears to have mortgaged his political future to it. It also makes the party seem uninterested in principle or policy.

And what if a defeated Brown government actually manages to win its mooted polling-day referendum on electoral reform? Mr Clegg may have closed one embarrassing question down, but he has not yet solved entirely the historic Liberal dilemma.