Foreign policy is dominating U.S. political discourse for the first time in years. This backgrounder looks at the leading schools of foreign-policy thought on both sides of the political aisle.

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…

Whether to engage heads of rogue states, a perennial foreign policy dilemma, has emerged in the 2008 U.S. presidential campaign.

News reports say the United States may be shifting its approach toward North Korea in an ongoing effort to get Pyongyang to give up its nuclear program. But some experts say that with negotiations st…