Politics, like daily life, is suddenly upended by coincidence. A couple of polls showing the Tories up, and Labour down. Then Margaret Thatcher announces what until then had seemed unimaginable - that she will belt up, too frail to carry on. Then the Tories' spring conference at Harrogate finds Iain Duncan Smith, former hard man of the hard right, going on about the excluded and the dispossessed. Could they do it? Could they really bounce back from that shattering defeat last year?

The answer, in theory, is "of course". If new Labour continues to dwindle in popularity and fails to deliver the public sector improvements it promised, and if Tony Blair finds his Afghan war becoming bogged down and bloody, and if he then tries to join a further ground war against Iraq; and if, meanwhile, the Tories come up with plausible and popular ideas on health and crime . . . well, all right, fling in enough "ifs" and anything is possible.

Shrinking turnout at the polls is part of the story. You have to assume that there are more people now who are not voting because of their disillusionment with the government, rather than it being a protest against the opposition parties. The more the turnout falls, if this is right, the more a sitting government is in danger from an unpredicted lurch in opinion among the shrinking number of actual voters.

In our aggressive, harshly judgemental media culture, Tony Blair has morphed from a grinning Mr Popular into a national hate-figure. It is hard but not impossible to run the story on a few years and see Duncan Smith just beating him.

Certainly, the Tories have played the post-election period very well so far. They have had the discipline not to talk about Europe. They have leashed their nastier instincts on immigration, crime and sexuality. They have banged on about health and schools, crime and the railways, hardly deviating, despite many temptations.

Michael Howard has reversed their old thinking on tax cuts and public investment and has paid public penance over independence for the Bank of England. Liam Fox is rarely seen without a serious social democrat-type doctor from some leftish corner of Europe at his elbow. The predictions of a jump to the loony right, so gleefully predicted by Downing Street after IDS won, have been proved wrong. The Tories, in short, give every impression of actually having listened to the verdict and views of the electorate last year.

All this while, it need hardly be said, Labour has got almost everything wrong. It has failed to improve anything at home very much. It has hectored and got into trouble with the Commons. It has been defined by rows about spin-doctors and party donations. If the old saying about oppositions not winning elections, but governments losing them, is true, then this lot are going about it the right way.

All of that is what my head tells me. Like most commentators, I have watched the past year with growing incredulity. I have had to rub my eyes and ask: are the Tories really not dead after all? We all have to examine our prejudices from time to time. Maybe IDS, Michael Howard and the rest are really quite appealing to the swathes of Middle England who kept Margaret Thatcher in power all those years - and they, with their big suburban houses, nippy German cars and nasty newspapers, certainly have not gone away.

But then I turn on the radio or the television and this unwilling suspension of disbelief just crashes to the floor. Duncan Smith may be a decent cove, but he a) is not very bright, and b) still speaks with all the passion and vision of an automated lift, or a BT recorded message. Victor Meldrew appears to be throbbing with energy and life-force, by comparison. And Duncan Smith's "eye-opener" on the estates of Easterhouse in Glasgow only illustrated just how out of touch this Tory leader is with much of the country he seeks to lead: did he think, before his visit there, that the kids dressed in knickerbockers and Alice bands and played chess all day?

Behind him are a motley bunch, some pleasant, some not so, but above all, virtually unknown. David Davis is the best communicator of the lot, but continues to giggle too much, and you still wonder whether his eyes aren't focused on that tempting space between the wing commander's shoulder blades. To go for these Tories now, the British people would have to be really desperate. And despite their irritation with new Labour, they are not.

The Tories lost a horrendous number of their experienced and talented MPs in 1997 and 2001. The electoral mountain they have to climb is gigantic. More important even than that, the time will come when they have to put some flesh on the vague, focus-groupy messages they are offering. They, too, will raise money from shady types and get into trouble for it. They will have to give us figures on whatever mix of taxes and compulsory insurance they are offering for the NHS, and many of us won't like the result. They will have to decide whether they back the 2004 agenda for Europe, and would live with the result of a euro referendum, or whether they're patriotic diehards - and that choice alone could split them.

But this spring, Labour has had a wake-up call that it must take seriously. More attention to parliament; less sanctimonious twaddle, and a frank admission of failures; a thorough reshuffle of ministers to bring in some fresh faces; a general acceptance that the country always has a choice and the Tories are neither mad nor disreputable - these are what we need in response to Iain Duncan Smith. After all, Labour has been so successful that it's changed IDS from Europhobic monomaniac to someone who currently sounds more like David Owen in the old days. Good politics is all about recognising your opponent's good arguments . . . and about realising that what seems to be coincidence is often actually a trend.