The mechanics of the contest are simple. On Tuesday, when MPs hold the first round of voting, the candidate with the fewest votes drops out of the race, leaving three to go forward to a second ballot on Thursday. The two winners' names then go out to the party membership who will select the next leader before 6 December.
Of the four candidates, only two are what in Vatican circles they term papabile - that is, manifestly suited to bearing the weight of the crown. Liam Fox has run an impressive campaign that has enhanced his standing. But he has failed to diagnose the seriousness of his party's ills, and his right-wing agenda simply would not chime with the electorate.
David Davis, on the other hand, has emerged from the campaign a diminished figure. He began as the favourite and had prepared the ground so well in advance that he is still likely to end up on the final shortlist. But from the pedestrian and narrow conference speech, to the blows he has aimed at David Cameron - a breach of his own assertion that Tory should not attack Tory - he has done himself few favours. Quite simply, he does not look up to the challenge of reinvigorating his party.
So it comes down to Cameron or the quintessentially English figure of Ken Clarke. We have said it before - that if the main duty of an Opposition is to hold the Government to account and give ministers a run for their money, Clarke is as visibly qualified as the Tories' last three leaders were not. Nevertheless, the very views of Clarke's with which we sympathise most - such as his stance on Europe - are, it has to be said, those least likely to impress his Westminster electorate. This is a shame, since he has fought a tenacious campaign that underscored his experience and, alone of the surviving candidates, also had the foresight to oppose the war in Iraq.
That leaves Cameron - a somewhat opaque figure, politically, for all the media exposure to which he has been subjected. So far, the good humour with which he has taken a relentless battering of questions about his past appears to have improved his standing. He may have had a privileged background but he seems to be made of what they used to call officer material, possessing a resilience under fire. He also, clearly, understands the need for the Tory party to present a more modern front. But we would like to see more definition of his policies on the economy, public services and the environment. We do not need an Opposition leader who is bright, young, personable and policy-free, but one equipped with a clear set of answers to the country's problems.
Many predict that by Thursday the contest will have been reduced to Cameron and Davis, one representing the glorious spirit of untried youth, the other the horny-handed champion of right-wing values. If so, more's the pity. This newspaper believes a far better contest would be between Clarke and Cameron. These are both strong, engaging and plausible opponents of an arrogant executive. For the Tory party to fail to see this would be another sign that they are still going nowhere. Only one thing is certain this week. The Tory party will have to gamble its future on a leader who is, to some degree, flawed. If it gets the decision right, the road back to power could reopen. If it gets it wrong, there will be many more years in the wilderness.