A deep look at how the US built the world's most expensive military — and how war profits and secret programs have warped its choices.

• The US spends more on its military than the next 10 countries combined, because it acts as global policeman with 800 bases in other countries.
• More than half the budget flows to five big contractors — Lockheed, Boeing, Raytheon, General Dynamics, Northrop — who face little competition and routinely overcharge.
• Those firms lobby lawmakers, use a "revolving door" of ex-generals, and spread factory jobs across states so no politician wants to cut spending.
• The Pentagon has failed six straight audits and can't locate 61% of its physical assets.
• The US sells weapons to over 100 countries as a currency for influence, but the leverage often fails — Saudi Arabia and Israel used American arms in ways the US opposed.
• After 9/11 the CIA ran secret "black site" prisons in dozens of countries and tortured suspects, which produced little useful intel and tainted real terror cases so masterminds may never be tried.

Outlook: Spending keeps climbing with no real political brake, and the same profit-driven conflicts of interest that fueled past wars remain firmly in place.