Truly, our system of government is a wonderful thing. The ratification of a treaty can go through virtually on the nod, as it did in the House of Lords last week over the Treaty of Lisbon. Another topic which was hotly debated in the Commons – the 42-day detention period – is, by contrast, the subject of a by-election, even though the parties divided on party lines.
There is a third kind of question: where the parties choose to agree with one another and to keep the public, as far as they are able to do so, out of the discussion. The example here is the war in Afghanistan.
Week after week, Mr Gordon Brown rises at Prime Minister's Questions and pays tribute to the dead. Mr David Cameron responds with a few well-chosen words. Sometimes, indeed, Mr Cameron becomes even more eloquent than the Prime Minister in his tributes to the fallen. Whereas Mr Brown has redefined the war as an "insurgency", Mr Cameron tells us that our troops are fighting for freedom on the very back streets of Britain.
Nor is Mr Nick Clegg far behind in tooting the trumpet. He did go so far as to wonder whether our boys would still be there in 30 years' time, in which case they would be grandfathers, if they were still alive. Mr Clegg did not make it wholly clear whether he welcomed their continuing presence in that inhospitable country or wanted them to be removed before then. No matter. The leader of the Liberal Democrats is content to remain part of the political consensus.
How much longer can it go on? When the body bags began to come back from Vietnam, later commentators in Britain used the phrase as a metaphor for casualties. They may have meant it literally. But old military men pointed out that, in our wars, soldiers were buried where they had fallen, as sailors were at sea.
In the past few years, certainly since the Iraq war, practice has changed. Casualties are returned, usually in a large transport aircraft, in a Union Jack-covered coffin, and buried with full military honours. And quite right too, if this helps the families. But these spectacles, shown more or less weekly on television, can do little to fortify the reputation of successive Labour governments.
For some reason, enlightened opinion in this country has chosen to depict the war in Afghanistan as a good war – at any rate, a virtuous war – and the war in Iraq as bad. Opinion in the Labour Party is, as we know, a different matter. Labour supported the Iraq war, and luminaries such as Ms Harriet Harman and Mr Jon Cruddas, not to mention Mr Brown himself, should not be allowed to forget that support. I have the division lists at home to prove it.
Labour had also supported the war in Afghanistan two years previously. Mr Tony Blair joined up as soon as Mr George Bush asked him. Indeed, Mr Blair was queuing up with sandwiches and a flask of coffee outside the front door of the recruiting office. The odd thing was that the representatives of enlightened opinion – the prig press, as much as Mr Rupert Murdoch's newspapers – seemed to be equally keen on what the Victorians used to call a punitive expedition.
In fact the US administration clearly had something on an altogether larger scale in its mind. The conflict soon became wider. Indeed, the kidnapping of suspects and transporting them to Guantanamo Bay (or its predecessor) began in 2001 in Afghanistan rather than two years later in Iraq.
I wrote here at the time that Mr Bush was acting out of pique, that the United States had suffered a grievous blow to its pride and that the President must be seen to be "doing something". The chosen course was to invade Afghanistan.
The majority of the plotters of the outrage of 11 September 2001 came from Saudi Arabia, though they lived all over the place, including Germany. Pakistan was as fertile a ground for the production of terrorists as Afghanistan, as it still is, if not more so. And yet, the Western powers would not contemplate invading Pakistan, any more than they would think of laying a finger on the Saudis.
In this country, the umpteenth Afghan war is being dressed up in the language of human rights, notably over the production of opium and the subjection of women. It is largely humbug. The United Kingdom became heavily involved in Afghanistan because Mr Bush asked us to become involved. That is the answer which Mr Brown, Mr Cameron or Mr Clegg should give when the curious voter asks: what are we doing in Afghanistan?
Mr Clegg is pretty hopeless, I am afraid. I doubt whether we shall get much sense out of him in the immediate future. Mr Cameron is playing the patriotic card for all it is worth, which may be less than he imagines. Mr Brown is, through the medium of his lugubrious Defence Secretary, Mr Des Browne, actually increasing our strength in Afghanistan.
Why not have a by-election on our presence in Afghanistan rather than on Mr David Davis's chosen subject? This is about the 42-day limit or, at its broadest, about civil liberties generally. These are undoubtedly important matters. But then, so is going to war.
For seven years, the political parties, all the newspapers and most of the commentators, not including myself, have been supporters of the war in Afghanistan. Mr Davis presumably supports the war, which is why the by-election is no kind of test at all.
Equally, however, Mr Davis's by-election as he has defined it is no test, either. He is at one with his party; he is still, I assume, an official candidate (even though it appears that the Conservatives are not supplying the funds); the other parties are not putting up candidates against him.
Mr Davis's action does not make sense, not because he is losing place and prospects (though he may be losing those as well), but because the result of the contest does not prove anything one way or the other.
This is the analysis of most politicians and political journalists, which I happen to share. But almost as soon as his decision was announced, Mr Davis began to receive messages of support: from public figures (including one from Mr Tony Benn), from people with electronic equipment at their disposal, not least, from columnists operating outside the sphere of politics.
Why, there is even a possible libel action in the offing after Mr Andy Burnham, a Cabinet minister, accused Ms Shami Chakrabarti of Liberty of whispering sweet nothings into Mr Davis's ear about his forthcoming resignation. In fact, Ms Chakrabarti prudently advised Mr Davis to stay put. I should advise Ms Chakrabarti to see the funny side of life.
And so we have a by-election where we have no candidates. We have a war which has been going on for seven years without troubling the political parties. And we have a Prime Minister who travelled to Brussels to receive the unanimous congratulations of his European colleagues for ratifying a treaty – subject to the decision of the High Court – without asking the voters any questions at all.