Other 10-year Cato spending cut estimates: Scrapping the departments of Commerce and Housing and Urban Development saves $550 billion; ending farm subsidies would produce nearly $290 billion. Cutting NASA spending by 50% would save $90 billion. Repealing Davis-Bacon labor rules produces $60 billion. Ending urban mass transit grants would save $52 billion. Privatizing air traffic control, as other nations have done, saves $38 billion. Privatize Amtrak and end rail subsidies and save $31 billion. Reform federal worker retirement, $18 billion. Retire Americorps, $10 billion. Shutter the Small Business Administration, $14 billion.

Defense spending should not be exempt from scrutiny. With such dramatic increases in appropriations, it is not plausible that all resources are being spent prudently. Defense Secretary Robert Gates has proposed savings of $145 billion over five years. That’s a start.

Entitlements—56% of the annual budget and growing—are the most difficult but also the most important programs to reform, because the total unfunded liability tops $100 trillion for Social Security and Medicare alone. The federal government does not put these liabilities on the books, but serious budgeting requires that we deal with this ominous long-term burden now.

The most complete work on entitlement reform comes from Wisconsin Rep. Paul Ryan, the new chairman of the House Budget Committee.