More turmoil in Iraq. A revered Shiite mosque is attacked for the second time, sparking fears of a new wave of sectarian violence. We speak to Damien Cave of the New York Times.

Fierce fighting continues today between Hamas and Fatah forces in Gaza. Our guest is Dr Rashid Khalidi, director of the Middle East Institute at Columbia University. His latest book is "The Iron Cage: The Story of the Palestinian Struggle for Statehood."

The US Army sets out some new rules for online blogs written by soldiers. We speak with Wired magazine reporter Noah Shachtman about the rules and with Army spokesman Paul Boyce, who says the rules are nothing new...just a clarification of what can be said on blogs.

Letters: we hear from you.

Frederick Wiseman, the dean of documentary verite filmmaking, continues his study of American institutions with State Legislature, which debuts tonight on PBS. Wiseman talks with us about following a session of the Idaho state legislature, made up of ordinary citizens, with his characteristic shots of the monumental and the mundane.