[This is an issue that sometimes comes up when chatting on other blogs, so may be a familiar position to come cyber-friends already. But I thought it'd be useful to put somewhere findable, anyway.]

Royals, eh? Who needs 'em? Bunch of taxpayer-supported parasites. Outdated, and they're no better than anybody else anyway. We should be a republic like everywhere sensible, right?

Well, no. The way I see things, we rather do need the royals.

Let me tell you a story.

Once upon a time in the dark era of George W. Bush, my future husband and I travelled round the world. In getting from Sydney to New York, we had to make a stopover in LAX, which is to say, Los Angeles airport.

Now, LAX was a horrible place, a ghastly place. Few airports are comfortable, but even fewer of them are staffed by security bristling with terrifying weapons and showing the kind of don't-even-think-about-it attitude towards paying customers on holiday that you'd normally expect to see from prison guards towards their charges the day after a riot. LAX was one of these unusual places. With a thirteen-hour flight behind us and a seven-hour one before us, and with no more dastardly intentions than to visit my sister and her family and maybe take a turn around Central Park while we were at it, it was genuinely frightening to find ourselves in a place that was working hard to convince us that we were one wrong turning away from a cavity search and a week in jail until someone could get hold of the British Ambassador. For an airport in a democratic nation, it felt strangely like being in a third world dictatorship.

But here's the thing that really clinched it. To enter this world of Dantean customer service, we all had to pass under an archway. At the top of this archway were two framed pictures - tatty ones, looking like they'd been cut from some cheap magazine - of George Bush and Dick Cheney. America mooning the world, was my second thought, but my first, instinctive reaction was the sense, as I said, that this felt like entering a dictatorship. Not just because it was Bush, though obviously that didn't help, but because putting the president up on the wall like an icon you pass under to enter the country is not the usual decorating choice in a democratic country. I'd been to quite a few democratic nations by now, and this was new, and threatening. Elected officials are not usually raised so high.

But, I wondered to myself, would Britain do something like that? I didn't think we'd put any face out so prominently ... but we might put a picture up somewhere in the airport.

The thing is, it wouldn't have been of the Prime Minister. It would have been of the Queen.

And in that moment, I realised I was a royalist.

Here's the problem. Some people have itchy knees; they need to genuflect to something, and if nothing suitable is around, they'll genuflect to something unsuitable. And that can be extremely dangerous.

Authoritarians like symbols; they like people to set above themselves and treat as an incarnation of the country and its values. If nobody else will do, they'll do it with someone who's supposed by their very nature to be first among equals and nothing more. But there is an alternative: have in place a traditional, unquestionably legitimate symbol - who can't do very much damage.

A royal family serves this purpose beautifully. Their whole function is, in a constitutional monarchy, symbolic. The Queen, God bless her, has practically no executive power. She sanctions and certifies various executive ceremonies in a way that confirms their legality, but this is ritual, and if she ever refused, I very much doubt her refusal would carry the day. It might cause a constitutional crisis, but one that would be entirely focused around the question, 'Okay, so how do we overrule the monarch?' The Queen can't propose laws, she can't take sides on them, she can't even vote. Her position, in practice, is that of a servant of the law, not a master or a maker.

So if people turn their icon-making towards her, it can do no harm at all. She represents the nation, but she lacks the authority to steer it in the wrong direction. Worship her all you like; it won't make her any more powerful.

Worship the Prime Minister though ... and now we're in serious trouble. Prime Ministers can steer the nation in the wrong direction. They do it all the time. And while there's often little the public can do to stop them - we wound up in Iraq despite massive protests - you never hear anyone suggesting that we should 'respect the office' of Prime Minister the way you often hear Americans suggesting one should 'respect the office' of President. No one says, 'Well, he is the Prime Minister' in that Mia-Farrow-in-Rosemary's-Baby voice ('Well, he is the Pope...') the way I've heard people say, 'Well, he is the President.' Nobody has very much respect for Prime Ministership; respecting the office is rare enough that there's pretty much no chance it will, in any way, impede people from exercising the good old British tradition of disrespecting the person holding it. We've had charismatic Prime Ministers who did inspire worship, usually to the detriment of the nation (Thatcher comes to mind), but there's no tradition of automatic respect for Prime Ministers. There's much more of a tradition, even among authoritarians, of assuming that the Prime Minister is a crooked bastard.

Which is extremely useful in a democratic nation. In a democracy, leadership is a job, and one that's supposed to place you subordinate to the needs of your citizens. Our Prime Ministers are far from consistent at doing that job well - but at least nobody thinks otherwise. Which limits what a Prime Minister can expect to get away with. Not nearly as much as it should, but a bit, and more than the alternative. People who want someone to worship don't need to aim it at the PM; they have royalty.

Royal families, in short, can act as a kind of siphon for authoritarianism. By existing to serve a symbolic, reverential function, they split reverence and leadership into two separate categories, leaving everyone free to remember that the elected leader may be nothing more than some tosser in a suit who'll get fired if we catch him taking bribes.

I don't reverence royalty, but I value it. Some people want kings. I'd rather they had one, safely contained within constitutional conditions, than that they made one out of a person with the real power to do harm. Because when that happens, we start forgetting what democracy really is.