As we move into the era of pluralist, multi-party, government it is clear that a lot of people are going to have problems getting used to the new world. Some are deliberately sticking to old formulae, whilst others clearly just haven’t caught up yet.

The most obvious example is the current discussion of whether the Tories have some sort of “first dibs” on setting up a government (coalition or minority) just because they are the largest party. This is a hang-over from two-party politics and majoritarian rule.

Let’s just do a simple thought experiment. Imagine a country where the voters are generally of a conservative predisposition, but the right is split between two roughly equally supported parties. The left – although clearly a minority of popular opinion – is united in a single party. Would anyone seriously stick to the idea that the “largest single party” should be the ones with some sort of moral authority to form the government? Or would they rather think that the largest coalition should rule, even though it’s made up of two “loser” parties?

In a two-party system it’s quite legitimate to think in terms of the largest party being able to rule, but as soon as you get into genuine multi-party territory it becomes nonsense. It is the biggest coalition that represents the largest group of voters, and ought to have the right rule – not the largest party.

The biggest, and simplest, coalition in our current parliament would be a Con-Lib Dem alliance, and that would also command a majority in parliament. But a Lab-Lib Dem coalition would be a bigger block of MPs, and represent many more voters, than the Tories left by themselves. So when neither could command a majority the Lab-Lib block would be best placed to rule (even as a minority government).

Our peculiar constitution also gives the incumbent Labour government an (in my opinion unfair) advantage. The Tories cannot in practice claim the right to rule as a minority unless either Labour resigns or are defeated in parliament. Unless other parties vote with the Tories or abstain, they can’t win such a vote. So they can be blocked. That is clearly something that needs fixing.

Things are not going to be easy for the civil service in this brave new world either. See my guest “Public Manager” column in Wednesday’s Guardian for a discussion on this as well.