"Where does the lion's share of our taxes go? As Paul Krugman puts it, the U.S. government is basically an insurance company with an army: Social Security, Medicare, Medicaid, and the military make up the large majority of federal discretionary spending. Everything else we normally think of as "government" - education, law enforcement, national parks, roads and bridges, unemployment insurance, food stamps, farm subsidies, foreign aid, art and science funding, international diplomacy - is a relative minority of the budget. (See here for a more detailed breakdown.)"
Adam Lee, One-Half of One Cent