Our series America's Briefing Book continues with former Supreme Commander of NATO General (Ret.) Wesley Clark helping us find out what President-elect Barack Obama needs to know about NATO. Clark names some external security challenges for Barack Obama, including finding the right way to get out of Iraq. He says this accord between Iraq and the U.S. is positive but not the final answer. Clark also says we have to have a strategy for Afghanistan that works and use non-military units of power more.