Tariffs have been applied over the years to protect homegrown industries and target competitors who are seen as using unfair trade practices. They impose costs on both importers and exporters and had been in decline until the recent U.S.-China trade war.

World powers continue to punish North Korea with economic sanctions, but the pressure has so far failed to push Pyongyang toward denuclearization.

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?

Hydraulic fracturing has unlocked huge reserves of shale gas and oil, transforming the energy outlook in the United States and the world, even as local opposition and falling world prices threaten th…