Fighting in Iraq flared up again Thursday and threatened a two-month-old truce between Shiite militias and U.S. forces and the interim governments. Margaret Warner talks with two experts about the insurgency and the security situation for U.S. troops in Iraq.

A fuel truck loaded with explosives blew up near a police station in southwest Baghdad early Monday, killing at least nine people and injuring more than 62 others, according to the Iraqi Health Ministry. Gwen Ifill speaks to New York…