Chris Hawes at The Wardman Wire has written an excellent piece today on constitutional reform arguing against some of the fads of the moment, like proportional representation and fixed-term parliaments. I’ve already written about fixed terms; and I agree with him about PR, too. The right place for it in our system would be in the House of Lords. To have the Commons elected by PR would risk a politicians’ politics of permanent coalition, in which MPs, not voters, choose who will govern, where we will be unable to sack the government, and where our influence over it will be smaller even than it is now. What PR can usefully do, though, is prevent the tyranny of the majority; that’s why it’s perfect for a revising and delaying chamber.

I’m not against all constitutional change. Devolution is a good thing, I think (although there is an English dimension yet to be resolved – I’d have only English/English & Welsh MPs voting on purely English/English & Welsh matters), and I back the Human Rights Act and freedom of information. I wouldn’t oppose a bit more use of the referendum, open primaries for Parliamentary selection, or a recall mechanism as long as it’s triggered by some independent finding of misconduct in office, rather than just political opposition. Tinkering is good.

But what Britain faces now is a political crisis, not a constitutional one, and politicians desperate to cling on to power should not be allowed to use it to toy with the constitution in their own narrow interests. If Alan Johnson is Prime Minister next week, he should not take that as any sort of mandate to bring in PR: that would be an obviously self-serving move from a Labour Party whose best hope of avoiding years or wilderness could be to offer this sacrifice, and coalition, to the LibDems.

Meanwhile, this week’s Prime Minister has launched a laughable “Council on Democratic Renewal” which seems to consist of ministers themselves plus a few great and good invited speakers. The only purpose of this stunt is to allow Brown to pose as “ahead of the curve”. It is the least democratic possible way to propose any reform, and this fag-packet “council” should meet as little as possible.

In particular, the suggestion Britain should have a written constitution is especially dangerous. It may be a superficially attractive idea: it sounds so “modern”, doesn’t it? But many people fail to realise it would mean a total constitutional revolution, abandoning what’s long been the keystone of our democracy: Parliamentary sovereignty. In countries with written consitutions, it is that written document which is sovereign – not democratic institutions nor, ultimately, the people who elect them. In countries like the US and Germany it is unelected judges who determine policy on smoking bans, abortion and gun ownership; in the States, it’s beyond doubt that Justice Scalia is one of the most powerful people in the country. Who elected him? It would be a disaster if Lord Phillips were as powerful here.

I’m a great admirer of the German and American constitutions, believe it or not: both countries had good reasons for adopting written consitutions at the moment they did, each is about as good a system as can be consciously devised by men, and each has stood the test of time. Americans are rightly proud of a system that has worked so well for two hundred years. But Britain’s constitution in the 21st century should not be based on the political ideas of the eighteenth; nor do we need arrangements designed above all to prevent the return of fascist dictatorship. Our constitution has the advantage of having evolved over time – and it has indeed evolved since King and Parliament vied for power, a contest that’s still built in to the American constitution’s frozen music. We’ve moved on since then.

Parliamentary sovereignty is a good, soundly democratic principle. People here would miss it, and only realise what they had when it’d gone. Politicians should stop toying with the fundamentals of the constitution.