In particular, Nick Clegg, Vince Cable and other Lib-Dem MPs have been accused by the National Union of Students of breaking an election promise not to support an increase in tuition fees for university students. This alleged breach of promise is cited by some as a justification for the vehemence and violence of the protest against such policy proposals.
The duties that we have to keep our promises are not always overwhelming. They can be overturned by other duties. When we make promises, we often create fresh moral duties for ourselves and fresh moral rights for those we make promises to. However, our other moral duties do not thereby evaporate. Often, our pre-existing moral duties can clash with and overwhelm whatever fresh ones our promise-making might create.
There are two sorts of promises. Suppose that, out of the blue, a father says, unconditionally, to his daughter: "I will take you to the circus next week - that is a promise". We might call this a one-sided, gratuitous promise. Suppose that another father says to his daughter: "If you wash the car, I promise to take you to the circus next week". We might call this a reciprocal, conditional promise. If this child washes the car but is not taken to the circus, she is deprived of something she deserves and has earned. She is treated unjustly. This child has, in the circumstances, the grounds of a justified grievance.
Reciprocal, conditional promises are ethically more binding than one-sided gratuitous ones. If we voluntarily accept the benefits of a particular agreement, we ought to accept the attendant burdens. By making a reciprocal, conditional promise, the father has created for himself a particular moral duty to take the child to the circus if she washes the car. Even if the fathers are, because of their promises, under some sort of an obligation to take their daughters to the circus, the obligations are far from absolute. They might well be over-ridden by other considerations.
For instance, if it turns out that the mother of one of the fathers dies and is to be buried on the only suitable day when the child might have been taken to the circus, it is clear that, despite whatever promises have been made, the father and his daughter should attend the funeral rather than the circus.
Suppose that the fathers discover that animals are mistreated by the circus.They might well think that, whatever promises they have made, they ought not to take their children to the circus.
The fathers were wrong to make promises to their children. Wiser parents would have stressed that the proposed visit to the circus was conditional on many factors, not all of which were predictable or specifiable.
Trust is of crucial importance in public life. Trust is eroded when politicians and other people in authority do not do what they promise or appear to promise to do. Other things being equal, politicians should be true to their word and keep their promises. However, other things are not always equal. Often, when politicians make or appear to make a promise or pledge, it would merely compound their error were they to keep it. Typically, they have duties that outweigh their duty to keep their promises and pledges.
For this reason, politicians should refrain from making promises and pledges. If politicians think that, in the circumstances, it is best for their constituents, and for the citizenry in general, that a particular policy is adopted, they should support it. If they promised in their election campaigns or in their political party manifestos to pursue a contrary policy, they should apologise for their promises and their manifestos and then ignore them.
Despite a popular view to the contrary, governments do not require any particular "mandates" to adopt specific policies. The authority of a government arises from being the government. Governments have a duty as well as a right to govern. It is not their duty to put into effect an election manifesto but to govern as they sincerely believe to be appropriate.
Some promises and pledges are of a contractual or quasi-contractual sort. To break them is unjust. Election promises and pledges are not like that. Members of Parliament represent the constituents who did not vote at all and who voted for other candidates no less than they represent those people who voted for them. Similarly, it is the duty of a government to govern the country in what it sincerely believes to be the best interests of the country. It is not its duty to implement election manifestos.
It would be outrageous if, prior to an election, a candidate said to an elector: "If you vote for me, I promise that I will wash your car or, if you prefer, give you 20." It would be even worse were he, in return for a vote, to promise to support a particular policy that he would not otherwise have supported and does not believe in.
If they are promises at all, the supposed promises and pledges of the politicians are one-sided, gratuitous ones rather than reciprocal, conditional promises. When politicians fail to fulfil their election programmes, the electors are not thereby treated unjustly no matter how annoyed, cheated and disappointed they might feel.
If you do not know what you will find when you turn a corner, you should refrain from making promises and pledges about what you will do when you get there. You should, instead, indicate your hopes, aspirations and intentions. That is the honest thing to do.
• Hugh McLachlan is Professor of Applied Philosophy at the School of Law and Social Sciences, Glasgow Caledonian University.