Editor’s Note: The savage fighting in Syria and now Iraq seems to grow worse every month. As the U.S. role in the conflict grows, so too does the need to understand the motivations of the fighters, inclu...

The Arab world’s foreign fighter problem makes the West’s concerns seem minor. Specific numbers should be treated with suspicion, but the current estimate is that there are roughly 15,000 foreign fighter...

Editor’s Note: The return of U.S. military advisors to Iraq and U.S. airstrikes against the Islamic State in Iraq and the Levant have dashed hopes that the United States would be able to put the latest c...