The answer must lie primarily in the nature of the recession that has just ended. In contrast to the manufacturing slump that marked the beginning of Margaret Thatcher's premiership, the recession of 1990 hit Conservative constituencies harder than it hit the Labour heartlands. While it was manufacturing industry and the North Midlands that felt the pain a decade ago, it was in service industry and the South-east where belts were tightened most this time round. The collapse of the housing boom made things worse still for Tory voters, by burdening them with negative equity when the deflating bubble drove the value of the homes they had bought below the mortgages they had taken on.
The research reported on our home news pages today helps to explain why recovery from the latest recession has not yet begun to help the Tories' showing in opinion polls as much as it should. Analysis of economic conditions in the Tory marginals - the 50 or so seats that will matter most in the local and European elections - shows that unemployment is falling and house prices are recovering more slowly in these areas than in the country as a whole.
The burning anger felt by Tory supporters in 1992 may now have dissipated. But it has been replaced by little more positive than a sullen apathy. Voters are not yet ready to forgive the Government, or John Major, for the hardships they have suffered during the past 12 months. Hence the difficulties Tory party managers in the shires expect to face in winning at the coming polls.
In the short term, Mr Major and his cabinet colleagues can do nothing to make the job of mobilising their supporters easier. The medicine that is politically tempting to administer - a further cut in interest rates - now comes with the economic side-effect of public disapproval from Eddie George, the Governor of the Bank of England.
With such limited room for manoeuvre, the Tories must therefore expect a long, slow haul back to levels of support that might justify calling an election. To have any hope of forming the next government, they must delay the dissolution of Parliament as long as they can. Yet there is one consolation. The ERM disaster, which dealt such a blow to Tory authority at the beginning of the current Parliament, will by then be that much more distant a memory.