THE OATH is a spectacularly gripping documentary that unspools like a great political thriller. It's the cross-cut tale of two men whose fateful meeting propelled them on divergent courses with Al-Qaeda, Osama bin Laden, 9/11, Guantanamo Bay Prison and the U.S. Supreme Court. Directed by Laura Poitras-director of the Oscar-nominated My Country, My Country-and winner of multiple awards, including Best Documentary Cinematography at the 2010 Sundance...