The purpose is for those people are receiving the greatest benefits of society (those who have the highest incomes) to pay a fair share for supporting the society that is enriching them.
^ This.
That's a bit of a peeve of mine. Saying that everybody should pay their fair share is tautological. The defition of 'paying a fair share' is (or is close enough to) 'what people should be be paying'. Nobody's going to come out and say 'I think that people should not pay a fair share'. The actualy debate is what a fair share is, and having people clutter up discussion with tautologies like that just gets in the way. Saying that people should pay their fair share without defining what it is just a way of trying to get people to agree with you without saying or contributing anything.
I'm not sure I agree, since some people do not agree that anyone wealthy does need to pay a 'fair share' back to his society.
Anyway, since a lot of smart people in here, could somebody tell my why rich people are scared of paying more in tax, so that the middle class can grow, so that more people can buy their products, rather than them just getting more money, and the poor being unable to buy anything? Maybe it's just me, but this economic crash seems to come from exactly that. People can't spend any money, because the rich have gotten them all in tax cuts for them.
But I'm probably just an evil communist worshipping the devil with my gay ass in my communist country cursing at Jesus because we're jealous of America's eternal glory.
Or something.