Who are they to pass judgement?

DOES a local constituency party have the right to eject its MP from government? The resignation of Tim Yeo raises two constitutional precedents. The first is that constituency activists, possibly unrepresentative of the wider party, have taken it upon themselves to decide the future of a minister. The second is that they have done so purely on the grounds of their MP's private life, not on his suitability as a minister.

A constituency party has one fundamental right: to choose its candidate. If the Conservatives of South Suffolk feel Mr Yeo's behaviour makes him an unsuitable representative, they are perfectly entitled to choose someone else. What they do not have the right to do is tell John Major that a minister he has chosen for his government is no longer to serve. There has been no past occasion on which constituency pressure has forced a minister's resignation for a purely private fault.

In the past, ministerial resignations because of personal fault - Profumo in 1963, Parkinson in 1983, Mellor in 1993 - have not been on grounds of private morality alone. Profumo, it was alleged, was a security risk; Parkinson had deceived the mother of his child by twice promising to marry her, then rescinding the offer; Mellor had broken government guidelines on accepting hospitality. In each case, the ministers concerned had lost the support of public opinion; and, in the cases of Profumo and Mellor, the support of the influential backbench 1922 Committee as well. That does not appear to be the case with Mr Yeo. His resignation has been forced by pressure from local constituency activists. And no one knows whether they represent the Conservatives of South Suffolk.

There are numerous instances of MPs losing the support of their constituency associations, but these have been mainly on policy grounds. Conservative MPs may have been insufficiently enthusiastic about capital punishment, or Labour MPs insufficiently left-wing to meet the predilections of their constituency supporters.

In one famous case in the Fifties, Nigel Nicolson, the Conservative MP for Bournemouth East and Christchurch, fell foul of his constituency association because of his opposition to Sir Anthony Eden's Suez adventure. The constituency association eventually decided to hold a ballot of all its members, which went marginally against Mr Nicolson. He was replaced by a new candidate at the next election. That is the procedure the Conservatives of Suffolk South ought to have followed if they felt that there were grounds for dissatisfaction with their MP.

There are grave dangers in the path that the Suffolk South Conservatives have taken. Constituency government, as Walter Bagehot pointed out, is the direct opposite of parliamentary government. The danger is of a moral witch-hunt that would leave very few MPs safe from persecution.

Constituency activists are far too censorious about the private lives of politicians, and not censorious enough of their public activities. Kenneth Baker and William Waldegrave can waste up to pounds 10bn of public money on the poll tax, and there is not a peep from their constituencies. Douglas Hurd can relax the guidelines on arms to Iraq two weeks before the invasion of Kuwait, without risking the slightest degree of hostile constituency reaction. So it is that politicians are likely to believe they can get away with anything in their public lives so long as their private lives pass muster - or so long as they are not found out.

Everyone has the right to judge politicians according to their own standards of morality. But let the public judgement of politicians be based on their contribution to the public good. Any alternative course involves replacing such public standards of judgement with an uncharitableness that goes against the tenor of our public life. Let us be saved from the self-appointed moralists of our society, many of whom are by no means spotless themselves, especially perhaps when these moralists have acquired positions of local leadership in a great political party.

The writer is Reader in Government, Oxford University, and a Fellow of Brasenose College.