A heated debate about whether America's actions in the Middle East set the stage for the 9/11 attacks.

• The fight centers on the old "chickens coming home to roost" line — the idea that 9/11 was blowback from US foreign policy.
• One side rejects the harsh framing but fully agrees America's choices helped cause the attacks.
• The argument: US support for jihad in Afghanistan and Middle East wars helped create Osama bin Laden and al-Qaeda.
• Even neocon Robert Kagan is cited as recently admitting 9/11 grew out of bad US foreign policy, just in softer words.

Outlook: Expect this blame-America-or-not fight over Middle East policy to keep flaring as the US weighs new involvement in the region.