This is because no political party for decades has won the votes of more than a third of the electorate let alone half. Therefore it cannot be said more than half the target market had been 'fooled'.
Does anyone doubt that politicians lie? Politicians know we know they lie, not least because they themselves work so hard to point out each others' fibs. Labour snitches on the ConDem coalition and the SNP, the Torygraph snitches on Labour. The question isn't why they lie, the question is how they keep a straight face when they are doing it.
After all, they are all honourable (and right honourable) men and women, our MPs in Parliament. We know because they tell us so. So why do they use deceit and dissembling as a key tool in getting their jobs, and getting into power? The answer, of course, is because it works.
Taking a Conservative Party leaflet as an example, our guest author, Barrie Singleton (author of the Spoil Party Games blog), provides an insight below: