I admit it's a puzzle. It could be ego, I suppose: a vainglorious belief in a transcendent personal destiny which, though delayed, cannot be denied. He wouldn't be the first politician to fall prey to this delusion. Perhaps, less immodestly, he seeks a measure of vindication, a decent showing, sufficient to provide him with a place of respect on the party's front bench. Maybe he has no choice: like the recruit in An Officer and a Gentleman, he's got nowhere else to go.

Or maybe, just maybe, he's doing it for the party.

I know what you're thinking. He's the guy that brought the Canadian Alliance to this state: divided, discredited, in the single digits in some polls. How could he help, except by slinking off into oblivion? The most he could hope to achieve by his candidacy, you're thinking, is to deepen the party's divisions.

He can't win: that much is true. Those who conjure up a repeat of his initial triumph, a year and a half or so ago, on the strength of the continued loyalty he enjoys among anti- abortion groups and the religious right, fail to recognize how much broader his support was then, beyond his base. At the time - how long ago it seems - Mr. Day was seen as the candidate who could bridge the party's enduring philosophical divide, between ideology and pragmatism, principle and power. He was, it seemed, sound enough on policy to satisfy the party's hard-core, yet personable enough to appeal to the electorate at large.

As it turned out, he was neither. The minute he came under fire, he started jettisoning party policy; at best, he seemed uncertain about it. And as for his personal appeal, well, what more need be said? The social conservatives may still be with him. But everyone else is gone.

Suppose he is sensible enough to know this. Why might he persevere regardless? Because somebody has to be the standard-bearer for those social conservatives, and the issues they believe in? Perhaps. But more: Because he's the man who can keep them in the party.

Social conservatives are a deeply embittered bunch these days. In the humiliation of Mr.

Day, they see the humiliation of themselves. The reason he lost, they tell themselves, is not so much owing to any personal failings of his own, but because he is a populist conservative, a religious believer, a Westerner: Everything they are, and the national media are not. And indeed, they are not entirely wrong.

It isn't the social conservative "agenda" that drives them. Most social conservatives don't have an agenda, in the sense of a coherent program for change. They just don't want things to get any worse. And, as important, they want respect. They want to feel their concerns are taken seriously. They want to belong to a party whose leadership does not treat them as pariahs, or snigger down its sleeves at them.

Conservatives who do not share their point of view would nevertheless do well to pay heed to them. Over the last three decades, social conservatives have been a key part of every successful conservative coalition in the Western world. Yet the price they have extracted in policy terms has been surprisingly small. To the extent they have ever had an agenda -- perhaps they'd prefer Canada were not the only developed country without an abortion law of any kind, though that hardly makes them radical -- they have seen precious little of it enacted.

So it isn't necessary for Mr. Day to win to keep them on board. Nor is whoever wins obliged to pay more than the usual lip service to social conservative concerns, much as Preston Manning used to do. But it is necessary that they feel respected, and that they have some voice in the party. And for that reason, it is essential Mr. Day be somewhere in the picture. Other candidates may be social conservatives. But other candidates have not been anointed by suffering. Mr. Day is their man. They might still vote for the party without him. But they would be far less likely to stay active. And it is the activists -- motivated, committed, even a little fanatical -- on which any political party depends.

Even if he doesn't win, in other words -- or rather, assuming he does not win -- Mr. Day can still serve his party by running. I don't say this is his reasoning. But it may be true all the same.