To be sure the government can raise the tax rate on the rich. The real question is whether the government will collect more money from the rich by doing so. I believe our prior experience with such rates shows we will collect little more.
The rich will do all sorts of things to keep from giving money to the government. They can afford the best tax experts and advisors, are in a position to receive income via capital gains instead of salary, can move resources overseas, take advantage of tax shelters - you get the idea.
Furthermore, the President and his minions know all of this. Keeping the higher tax rate on "the rich" is theater, is playing to the class war audience.
Paradoxically, often times more revenue will be collected by lowering tax rates as lower rates encourage the receipt of income as fully taxable salary and encourage entrepreneurial activity.
