John Rentoul: First take off your head. Then run round in circles. Now elect a leader

Michael Howard - "forgotten but not gone" as Alastair Campbell described him last week - faces a remarkable possibility. It could be that the party members will say that they want the MPs to choose the leader, while the MPs could say that they want the party members to decide. Not since Ehud Barak and Yasser Arafat nearly came to blows in their efforts to usher the other first into a Camp David doorway has there been a more desperate case of "No, no, after you." The attempts of the two wings of the Tory party to avoid the blame for choosing the wrong leader for the fourth time running would be comical if the implications for democracy were not so serious.

The party now finds itself in a hideous bind. Howard wants to change the system brought in by William Hague, which gave grassroots members the final say between the top two contenders in a ballot of Tory MPs. He wants to go back to the previous rules, by which the MPs alone made the decision - after notional "consultation" with the wider party. But the proposal has to be supported by two-thirds of MPs and two-thirds of the members of something called the National Convention, which is part of the hidden wiring of British politics. It consists of the chairmen of local Tory associations, plus "area and regional officers, members of the Board and other senior volunteers". This activist élite is usually loyal to the leader, but Howard's attempt to push the change through after announcing his resignation has forfeited that loyalty. The other thing that we know about them is that they tend to be more pragmatic or centrist than grassroots members. In recent leadership contests, surveys of local association chairmen usually found two-to-one majorities in favour of Kenneth Clarke over whichever deadbeat loser eventually won. This time is no exception. A survey of 100 chairmen carried out by The Times this month found Clarke preferred to David Davis by the traditional margin. More intriguingly, it found them divided 51 to 34 in favour of letting the MPs choose the leader - a majority, but not the required two-thirds majority.

The grassroots members of their associations do not have a vote in next week's decision, but their views are worth recording. According to a YouGov survey, they differ from their chairmen in that they prefer Davis to Clarke by a narrow 48-45 per cent margin, but 63 per cent of them share the view that the MPs should decide.

As for the MPs, they have taken their heads off and are running around in circles. Several of them, including David Davis, still the front-runner, and other more surprising ones such as the Clarke-supporting Anne Widdecombe, say that they want the party members to choose the leader. Many Tories can be found roaming the half-empty corridors of Westminster while the builders install the new full-height security screens in the House of Commons chamber trying out phrases of sub-Luther-King rhetoric: "Once you give people the vote, it is impossible to take it away from them again." What? Even if they say they don't want it?

So the chances are that the rule change will fail, and that Clarke will face Davis in a ballot of all party members. Then the party faces new hazards, as the party in the country could well choose one while the MPs prefer the other - although surprisingly it is no longer clear which group would vote for whom.

Before that blood sport can begin, we have the diversion this week of the Liberal Democrats creating a little leadership crisis of their own. Unlike Labour and the Conservatives, their leadership elections are "pure" one member, one vote, with MPs having the same votes as other party members. The Liberal Democrat conference in Blackpool will debate a motion to require leadership candidates to be nominated by 10 per cent of their fellow MPs - that is, currently, seven. Could this be designed to block the ambitions of Simon Hughes, popular enough with grassroots members to win the party presidency yet so popular with his parliamentary colleagues that he holds the less-than-dizzying post of shadow attorney general? Nick Clegg and Chris Huhne, the leadership hopefuls of this year's new intake, will be watching with interest.

Then there is the most submerged debate of all, about the electoral college system for the Labour leadership. Gordon Brown's pre-eminence renders the main question irrelevant for the moment, but Labour researchers in Westminster are playing Guess Gordon's Deputy with growing anticipation. Will Brown decide who he wants and then ask the college to vote for a joint ticket, as John Smith did with Margaret Beckett in 1992? Or will he hedge and edge, as Tony Blair did with John Prescott in 1994, staying above the fray until it was clear who was winning? Alan Johnson, the Secretary of State for Trade, is favourite in the second scenario, but would Brown want to pre-empt him by choosing someone who poses less of a threat to his own position?

All grist to the mill of speculation, but there is an important issue underlying the debate in all three parties. William Hague made a strategic error of historic proportions when he changed the Tory party's rules in 1997. Perhaps he was trying to protect himself from imagined plots by supporters of Michael Portillo, or perhaps to copy Labour's success in presenting itself as more "democratic" when John Smith broke with the trade union block vote in 1993. The Labour Party introduced an electoral college in 1981 because the party in the country wanted to force its choice on a parliamentary party it could no longer trust. The Smith reform was an attempt partially to undo the damage of that decision. It was part of a necessary, titanic and symbolic struggle to separate Labour from the trade unions. That was done by giving the vote to individual union members, which had the presentational advantage of looking a bit like an American primary. But it is indefensible in a parliamentary democracy. The point about party leaders is that they have to have the support of their MPs - ultimately as prime minister they have to command the confidence of the House of Commons.

Yet there are members of the Shadow Cabinet who seriously propose copying Labour's original mistake with an electoral college of their own, with half the votes held by MPs and half by party members. It is all nonsense. MPs should choose party leaders: anything else is either manoeuvring for the advantage of one candidate or another, or it is public relations. The Conservatives should vote to let the MPs decide. That they seem bent on keeping the mad Hague rules is the worst possible start for the new parliament.