An increase in terror incidents involving Islamic radicals who are U.S. citizens is vexing law enforcement officials and posing new questions about the roots of their radicalization.

Five days after U.S. forces killed al-Qaeda in Iraq leader Abu Musab al-Zarqawi, the group announced his successor, the unknown Abu Hamza al-Muhajir. Speculation abounds about the man and the signifi…

Iran’s Supreme Leader remains the regime’s ultimate authority but controversy surrounding the country’s June 12 presidential election has raised new questions about the role and power of the head of …