Andrew Fieldhouse of EPI says less progressive taxes alone don't explain the huge rise in inequality in recent years. But what low tax rates spur rich people to do might explain more of it.
Compared to peer countries, the U.S. taxes the rich quite heavily. But it doesn't spread what money it collects as equitably.
An Obama presidency looks likely to do more redistribution from the rich to the poor and from the healthy to the sick, while a Romney presidency looks likely to do more redistribution from the young to the old and from taxpayers to defense.