Actually for 2005 is was $272B, or 12.5% of total government revenues. Considering government has been growing around 7% annually, I don't think it would be too drastic to to cut out 12.5% of spending while phasing out corporate taxes. Of course the $760B deficit needs to be eliminated first.
"A democracy cannot exist as a permanent form of government. It can only exist until the voters discover that they can vote themselves largesse from the public treasury. From that moment on, the majority always votes for the candidates promising the most benefits from the public treasury, with the result that a democracy always collapses over loose fiscal policy, always followed by a dictatorship." -- Alexander Tyler
This the the *major* argument for our present tax structure. For corporate taxes to be fair, tax policy *should* be either : (1) Corporations pay taxes on earnings. Therefore, dividends and capital gains should be tax free, or (2) Corporations should NOT pay income taxes and be a tax pass-through conduit, allowing for taxes to be paid on dividends and capital gains. The way things stand now: (1) Corporations pay corporate income taxes on earnings. (2) Dividends are taxed by shareholders (2nd time corporate earnings are taxed) (3) Shareholder pays capital gains tax (3rd time taxed) (4) Estate [if large enough] pays tax 4th time. It's really all quite immoral.