The Federal government got along just fine for 140 years with no income taxes, and income taxes only account for 41% of federal revenues. They now take in over $2.2 Trillion (59% of Obama's $3.8 T budget) annually from other sources. "Way back" in 2003, $2.2 Trillion was enough for the entire budget. All we need to do is cut back to the budget numbers from 2003 (when we were doing just fine), and we can eliminate ALL Federal income taxes. Just sayin'.
Not entirely fair, because while income taxes “as such” provide 47% of revenue, Social Security and ‘Social Insurance’ account for 36% of revenue.
http://en.wikipedia.org/wiki/File:U.S._Federal_Receipts_-_FY_2007.png
Now, were those ‘honest’ sources of revenue to provide for SS and ‘Social Insurance’, it would be one thing, but for decades the federal government has been immediately using those revenues as “faux income taxes”, preserving only a theoretical revenue (IOU’s) for SS and ‘Social Insurance’ spending.
But these two together amount for 83% of federal revenues.
Corporate taxes, excise taxes and other make up the other 17%. Far too little for the federal government to survive on. That is, as things are right now (as of 2007), total revenue is $2.3 trillion. With just that 17%, the federal government would have to make due with just $400B.
The Department of Defense alone spends $700B for normal outlays.