Are these simply more examples of lying politicians, out to pursue short term political advantage by whatever means? Possibly, but the outrage whipped up by certain sections of the media in each case is, in my opinion, somewhat misguided.
In both cases, we are talking about elections that failed to deliver a clear majority government, thus requiring negotiations between parties to deliver a stable result. There is nothing especially wrong with hung parliaments, minority rule or coalitions. Yet under such conditions, it entirely possible that pre-election promises will have to be broken or modified in order to reach a new agreement.
Consider the UK. We are governed by a coalition between a party who promised more nuclear power and to support the Trident nuclear programme and a second party that promised to end Trident and to build no new nuclear stations. How is it possible for such a coalition to not break promises?
I think there is actually too much emphasis on campaign promises (in the media and by politicians). Representative democratic government is not, despite all the rhetoric, about implementing the will of the majority. It is system whereby elected representatives are entrusted with the authority to make wise judgements on our behalf. A government that makes an unpopular decision is not thereby undemocratic since representative democracy is not about how decisions are made but how representatives are elected.
It is possible that many people do not like this and would prefer a direct democracy. While this has many advantages, especially in polities of a smaller scale, under our present conditions, I'm not sure I trust my fellow citizens enough (or rather the media that all too often guides us by the nose down paths of its own liking - or should I say, of Rupert's liking). In any case, it is not the system we have.
We consent to certain decision-makers, not to certain decisions. How then are we to discern who is to lead us if we are not simply looking for someone who promises to do things we like? All kinds of ways. We examine their history, their qualifications, their character, their party values, their voting record, their ability to demonstrate critical thinking in their public and personal communications, our impression of them from meeting them personally and engaging them in conversation, their ability to persuade, their ability to bring people with them, their vision for the future - and so on. While pre-election promises are clearly part of what we base our electoral judgements upon, they are a relatively small part of the package and must always be taken with a grain of salt in a world where politics is the art of the possible.