Every four years, U.S. presidential candidates compete in a series of state contests to gain their party’s nomination. The political process is one of the most complex and expensive in the world.

For many policymakers, economic sanctions have become the tool of choice to respond to major geopolitical challenges such as terrorism and conflict.

Nearly all nuclear weapon states, as a matter of policy, remain ready to use their weapons without having first suffered a nuclear attack.

President Trump has proposed steel and aluminum tariffs, citing U.S. national security interests. Some experts argue that his plan could provoke retaliation from countries like China, or even a trade war.

The Federal Bureau of Investigation has been reoriented toward counterterrorism in recent years, but continues to face charges of overreach.