YOU may well think of yourself as a liberal democrat.

Don't look so horrified; I used lower-case letters. In any case, you don't need to be Cratylus to grasp that it depends on what you mean by "liberal" and "democrat".

In America, "liberal" is a term of abuse, intended to convey the impression that the person thus labelled is some distance to the left of Trotsky, perhaps because he is in favour of gun control, or increased government powers. This usage seems not to be impeded by the fact that most of the policies favoured by such liberals are in fact illiberal, or at any rate offend libertarians. To confuse matters further, most of them are advanced by people called Democrats.

Though liberal may be abuse in the US, elsewhere it is a praise word. By contrast, "democratic" is a universally popular notion. So much so that some countries, such as the Deutsche Demokratische Republik and the Democratic People's Republic of Korea, actually put it in their names. Their citizens may not have been inclined to take the word for the deed, but it left despots free to murder and enslave their populations secure in their own righteousness.

The catchphrase "I agree with Nick", so briefly, mysteriously popular in April 2010, isn't heard much these days, but it would be a step too far to compare Mr Clegg to Erich Honecker or Kim Il-sung. All the same, he is currently taking an illiberal and undemocratic stance in support of an apparently liberal, democratic measure.

To put it bluntly, the Liberal Democrats are attempting to blackmail the Conservatives on tomorrow's programme motion on the House of Lords Reform Bill. This would impose time limits on discussion of the reforms, but perhaps as many as 100 Tories are expected to defy a three-line whip. If they succeed, the bill can be talked out.

This is bad for David Cameron's authority, but not otherwise terrible. The Prime Minister, though in favour of reform of the Lords (as, nominally, all the political parties are), doesn't regard it as a major priority. What with the banking crisis, the economy, health, welfare, education and pension reforms and all the other things which actually matter, he shares this view with anyone who isn't utterly swivel-eyed in their fixation on the minutiae of political trainspotting.

That would be the LibDems, now threatening to withdraw their support for boundary changes negotiated as part of the Coalition agreement – changes that are, incidentally, desirable both because they remove an unfair bias towards the Labour Party, and because they would reduce the number of MPs by 50. But in the Coalition agreement, Mr Clegg's party agreed to support them as a quid pro quo for a referendum on the Alternative Vote, not for Lords reform. What's more, the Coalition agreement doesn't promise delivery of Lords reform, but only that proposals would be brought forward.

The very fact that these were the Liberal Democrat concerns when negotiating their place in the Coalition, rather than, say, insisting they be able to keep their promises on university tuition fees, gives enough evidence of the silliness of the party's priorities. But to waste huge amounts of parliamentary time on pushing through a major constitutional change – though not one high up anyone's list of things needing doing immediately – at the very moment when Europe may be on the verge of total financial meltdown is lunacy of the first water. At the very least, proposed changes to the second chamber deserve to be put to the people in a referendum.

The reason sensible Lords reform has made little headway in the century since the Parliament Act of 1911 (introduced by the Liberals) is that that legislation removed all power from the Lords except for revision and scrutiny. Certainly, we may agree that the make-up of the second chamber could do with further revision, but it is not an affront to democracy by being unelected (any more than, say, the courts are), because the superiority of the Commons is not in question. Even so, the expertise in the Lords has been instrumental in preventing or reforming a good deal of bad legislation which sailed through the lower house.

This particular proposed reform threatens, perversely, to be less democratic than the current set-up. Any elected second chamber, even with its members on 15-year terms, challenges the legitimacy of the Commons. And with the likelihood that it would be composed of also-rans for Commons constituency nominations on a party list system under PR, it could actually bring down the standard of those engaged in political life (difficult to imagine, I know, but true all the same).

Yet this issue, not tuition fees or NHS reforms or welfare payments, is the one over which Mr Clegg and his disciples have chosen to nail their colours to the mast. Unsurprisingly, all the signs are that few Tory MPs, most of whom can see the flaws in this bill only too easily, will respond to the LibDem threats by caving in. On the contrary, it is likely to harden their resolve.

These tactics will surprise no-one who has ever encountered the Liberal Democrat approach to election campaigning, where they have a well-deserved reputation for being the dirtiest fighters in the business. But they're a poor technique to employ against your Coalition partners, especially since the LibDems constantly harp on about the superiority of forging a consensus in political life.

If Mr Clegg will not abandon this line of attack, relations between the governing parties could disintegrate to the point of confidence and supply fairly soon. The one cheering piece of news for the Prime Minister is that his Deputy and his followers are the people who have by far the most to lose from any collapse of the Coalition.

There are many Tory backbenchers and rank and file supporters who are already convinced that Mr Cameron's administration is insufficiently Conservative, and believe that too many concessions have been made. If Mr Clegg really believes in give and take, he must take a defeat tomorrow with good grace, and give up his pet notions. The rest of us have better things to worry about.