Successive U.S. administrations have sought to justify controversial domestic surveillance programs amid criticism from Congress and rights activists, explains this Backgrounder.

Rail infrastructure is a critical component of a transportation network capable of helping the United States compete in global markets. Efforts to expand and modernize U.S. rail, particularly to incl…

The U.S. government designates Iran as the "most active state sponsor of terrorism," which feeds concerns about Iran’s growing nuclear program.

New screening measures at U.S. airports are being called overly intrusive by some passengers and civil rights groups. National security experts advise using a system that relies more on intelligence,…

The war in Afghanistan hasn’t been a major campaign issue even as public support for it has waned. This Backgrounder examines political backing for the war.

The United States has pursued missile defense technologies for six decades, with mixed results. Changes under the Obama administration, including adjustments to planned defenses in Europe, could port…

International actors are redoubling efforts to restore Afghanistan’s agriculture sector and weaken the massive opium trade that helps fund the Taliban. But competing strategies and corruption could s…

Secretary of State Hillary Clinton, a senator and former First Lady, has offered a tough pragmatism on national security matters and called for reviving U.S. credibility in the world.