Editor’s Note: The Obama administration's nuclear deal with Iran remains one of its most important, and most contentious, foreign-policy legacies. Much of the controversy in the United States stems from ...

Editor’s Note: Since 9/11, the United States has pushed all its allies to crack down on terrorism to prevent them from launching attacks or aiding others who might do so. President Trump has doubled down...

Editor’s Note: The Islamic State and al-Qaeda are often, correctly, portrayed as bitter rivals: They compete for recruits and money, and in Syria their forces have repeatedly turned their guns on each ot...