But there seems to be something about the subject of university tuition fees which brings out the worst in politicians where keeping promises is concerned.
Back in 2001, New Labour went into the general election with the cast-iron manifesto pledge: “We will not introduce top-up fees and have legislated to prevent them.”
Less than two years later Tony Blair’s government duly introduced them, in the teeth of a backbench parliamentary revolt in which several leading North-East Labour MPs were to the fore.
If Liberal Democrat leader Nick Clegg had been more of a student of history, perhaps he would have reflected on this before issuing his similarly unequivocal pledge not to raise tuition fees in the run-up to the 2010 election.
Then again, had he done so he might have concluded that breaking promises is not necessarily politically fatal. After all, Mr Blair’s original broken pledge on tuition fees did not prevent him winning a third general election in 2005.
By the same token, keeping your election promises is no guarantee of political success.
Indeed, it was Margaret Thatcher’s determination to stick to a promise to reform the system of domestic rates that led to the disastrous implementation of the poll tax in 1988 and indirectly to her fall from power two years later.
But for the Liberal Democrats, there was something about breaking the tuition fee pledge that seemed to strike at the heart of what the party is and what it stands for.
Partly because of its strong activist base in the education sector, and perhaps also because of its level of support among students, the question of tuition fees had become something of a touchstone issue for the party.
It was certainly one of the biggest reasons why, in the North East, the Liberal Democrats had become credible challengers in seats with large concentrations of students such as Newcastle Central and Durham City.
So in this sense, for the party leadership to change its mind over the issue was always likely to be viewed as a betrayal on a par with a Labour leader calling for the privatisation of the NHS or a Tory leader announcing we should join the euro.
But this is not all. There was also something about the idea of breaking election promises at all that ran counter to the Lib Dems’ self-image as a party.
This is why the broken promise on tuition fees was such a watershed for the party – the moment it gave up – possibly for all time – any claim to be representative of a “new” or different kind of politics.
It is for all those reasons that Mr Clegg issued his videoed apology to party supporters this week ahead of what is certain to be a difficult party conference for him.
Whether it will do him any good however remains very much to be seen. Many of the party’s supporters are likely to take a fairly dim view of the fact that he appeared to be apologising not for breaking the ‘solemn’ promise, but for having made it in the first place.
Mr Clegg finds himself in a strange kind of political limbo. Despite the comments by Lib Dem peer Lord Oakeshott last month that any business that had lost so much market share would now be under new management, the coming conference week will not see any overt challenge to his leadership.
Yet at the same time, it is hard to find many Liberal Democrats who seriously believe Mr Clegg will actually lead them into the next general election in 2015.
The remorseless logic of their plight is that if they are to present themselves to the electorate as a viable alternative to the Tories as well as to Labour, it will have to be without the man who took them into a Tory-led coalition.
But that is next year’s Lib Dem conference story. For now, Mr Clegg continues to inhabit the ranks of the political living dead.