If there's a problem with the Unspoken Constitution its that it barely qualifies as satire. The shenanigans surrounding MPs' expenses, Carter-Ruck's single handed attempt to rewrite the UK constitution to favour their client Trafigura and this torrid little paper sneaked out by the Ministry of Justice today (which patiently explains why Royal Prerogative powers are, in fact, all wonderful and the only thing that stands between us and authoritarianism), all amply illustrate that Stuart Weir and co's attempt to write the famously unwritten constitution is more a reflection of reality than an exaggeration of it. A Modest Proposal is satire. Yes, Minister and The Thick of It are satires. The Unspoken Constitution is merely frank.

I have to admit to finding this week somewhat depressing in that it is clear that a great many MPs have returned from recess determined to shut down any further discussion about reform and that, to an extent, they are succeeding. The media itself has been very helpful in this respect, detailing the process almost moment-to-moment but almost entirely lacking in analysis. Let us not forget that the people who are now complaining about the unfairness of Sir Thomas Legg applying new rules to them retrospectively are for the most part the same people who attempted to keep this little scam of theirs shrouded in secrecy - in defiance of the law - for years. All the indications are that for the most part, they still haven't learned why that was an utterly stupid and damaging thing to do.

The media, frankly, loves the status quo because it means it can write about politics on its terms. Everything can be about story; the notion that politics is about a battle of ideas takes a back seat. There has, if truth be told, always been a tension between the two, but the latter took a distinct turn for the worse 20 years ago and has never recovered.

The paucity of vision in politics today was on display at the Vote for a Change/All-Party Parliamentary Group for the Continuation of First Past the Post debate on Tuesday. I won't attempt to sum up the debate because there wasn't one to speak of; as Oona King pointed out very early on, almost everyone in the room had made up their mind already so what was the point? But I was struck by the number of MPs who stood up and waxed lyrical about how they regard their main role being to represent their constituents and their constituency, above all else.

Historically, that is quite a new notion and I know it is a notion that has a lot of support within the Lib Dems. But it is a dreadful one nonetheless. MPs' primary role is to scrutinise - both the executive and legislation. Their first duty should be to the national interest, surely?

I'm not suggesting, incidently, that a sense of place for MPs is unimportant or that local issues should play no part. My beef is with the notion that this should be the priority. What's worse is that it is a fiction to suggest that they do. Most MPs put party loyalty above parochial concerns most of the time. Local campaigns can force them to abstain or even defy their whips, but only if a lot of pressure is created. True, MPs are generally more likely to defy the whips than at any point in the recent past, but this is still the exception rather than the norm.

Either way, the notion of the MP as an independently minded individual who cares passionately about working within the system to bring forth their vision of the good society is extremely unfashionable. This is true whether we are talking about party politics or even this current vogue for indpendents; in fact, when it comes to the Martin Bells, Richard Taylors and Jury Teams of this world, ideas appear to have gone out of the window entirely - at least political parties have manifestos still. What I found on Tuesday was that the supporters of FPTP were united in arguing for this idea of parliamentary politics.

It's a real problem for supporters of proportional representation because it is an argument that holds real resonance amongst the public. Who wouldn't want an MP who is committed to doing whatever you tell them to do (leaving aside the fact that there will be 70,000 other constituents with competing interests for one second)? This idea of the ultra-local politician has taken a firm grip in the popular psyche; people even imagine that it was ever thus.

The problem for electoral reformers is that thus far we have failed to take on this argument. Worse, a great many electoral reformers actually agree with it. I've lost count of the number of times I've heard people tell me that they are a) pro-proportional representation and b) in favour of retaining the constituency link. It is one of the main arguments that people who support the Jenkins system assert.

I don't believe we can ever win the argument for proportional representation until reformers can agree that what we need is a radically different kind of politics. Each time someone argues for essentially the status quo with a few tweaks to neutralise the worst aspects of it, they concede almost all the ground to the other side. It becomes, essentially, a narrow and technocratic argument about systems and practicalities. The moral force behind the argument for PR is entirely lost. We might as well not bother.

Ultimately this argument applies to the reform debate more widely and brings me back to The Unspoken Constitution. Our current system has become so toxic that the time for incrementalist change is now past. We need a fundamental shift, not an attempt to meet the status quo halfway. Tim Garton Ash is correct when he says that the Lib Dems aren't arguing for this any more and that it is a crying shame. What's odder is that Nick Clegg's language nine months ago - before the MPs' expenses scandal erupted - was significantly more radical. Even Cameron comes across as more forthright on this area now, even if he is hopeless when it comes to specifics.

Maybe it doesn't poll well, but I'm not convinced that sounding like everyone else does either. Either way, the lack of a clear iconoclastic liberal voice in this debate at the moment is lamentable.

Cross-posted from the Quaequam blog.