National Security

U.S. Marines with 3rd Battalion, 5th Regiment and the Afghan National Army provide cover as they move out of a dangerous area after taking enemy sniper fire during a security patrol in Sangin, Afghanistan, in November 2010. During its seven-month deployment, the 3/5 sustained the highest casualty rate of any Marine unit during the Afghan war, losing 25 men.

Lt. Col. Jason Morris pays his respects at a memorial service in Sangin, Afghanistan, on Nov. 26, 2010, for three Marines who were killed: Lance Cpl. Brandon Pearson, Lance Cpl. Matthew Broehm and 1st Lt. Robert Kelly. Morris commanded a battalion in volatile Helmand province that suffered the highest casualty rate of any Marine unit in the Afghanistan War.

Phil Pressel designed cameras for the government's top-secret Hexagon project. He's only recently been able to speak about his life's work.

This undated photo provided by the National Nuclear Security Administration shows the last B53 nuclear bomb. It was dismantled this past week, just outside Amarillo, Texas. It's a milestone in efforts to reduce the number of nuclear weapons.

Protesters hold up signs outside of Federal Hall during a demonstration against then-U.S. Attorney General John Ashcroft in 2003 in New York City.

Republican Sen. Lindsey Graham of South Carolina has criticized the Obama administration's stance on the detainee policy in the defense bill.

This image released by the SITE Intelligence Group on April 27, 2011, shows Thierry Dol, one of four French hostages held by al-Qaida's North Africa affiliate. U.S. counterterrorism officials are concerned that al-Qaida affiliates in Africa are growing stronger.

A drop house raid yielded several suspected illegal immigrants on April 29, 2010, in Phoenix. Northwestern University political science professor Jacqueline Stevens says some of the nearly 400,000 people deported during the past fiscal year weren't illegal immigrants.

A U.S. Marine Osprey at Camp Leatherneck in southern Afghanistan. The aircraft suffered multiple problems when it was being developed, but is now getting praise from those flying it.

Lance Cpl. Dakota Hicks, from Laharpe, Ill., connects a radio battery to a portable solar panel system in Sangin District, Afghanistan.

President Obama speaks in the White House Rose Garden to discuss the death of Libyan leader Moammar Gadhafi.

In southern Arizona, troops take part in a large-scale search-and-rescue exercise called Operation Angel Thunder.