With economic inequality at an all-time high, some U.S. presidential candidates are proposing dramatic shifts to the U.S. tax code. How have similar plans worked elsewhere in the world?

Backgrounder examines the Intermediate-Range Nuclear Forces (INF) Treaty, which may now be imperiled by mutual suspicion between Russia and the United States.

Charges of foreign power interference in the U.S. presidential election have raised grave national security concerns and touched off multiple federal inquiries that could drag on for months.

U.S. strategic and tactical nuclear weapons on land, in the air, and at sea, will undergo costly and extensive modernization in the coming years.

The separation of powers has spawned a great deal of debate over the roles of the president and Congress in foreign affairs, as well as over the limits on their respective authorities, explains this …