Backgrounder: Ongoing sectarian troubles and corruption threaten Nigeria’s future security.

Nigeria has made progress since its return to democracy in 1999. But a political system crippled by corruption and dogged by ethnic tensions threatens to derail the country from its path toward good …

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

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…