The richest 1% of Americans pay a 21% of all the taxes. That really sounds like a lot of money, until you compare that number to another relevant piece of information: the richest 1% of Americans make 21% of all the income. This study from Citizens for Tax Justice (via) gives a good idea on how the tax system really works:
If we take into account all three levels of taxation in the US, the system as a whole is far from progressive: what we have is, essentially, the world´s most convoluted flat tax in the planet. The Federal tax system, with all its loopholes, it is fairly progressive; the state and local taxes, however, are incredibly regressive almost everywhere in the country. Connecticut, despite having a progressive income tax, follows this pattern, due to the extremely nature our local property tax system. Despite all the chatter about soaking the rich, the facts point out on the opposite direction.