With no more limits on intermediate-range missiles, the Pentagon is embarking on a test of once-banned systems. 

A mysterious August explosion at a Russian missile test site likely involved a prototype nuclear-powered weapon. 

Following the end of the INF Treaty, the United States tests a ground-launched cruise missile, and Bolton is out as National Security Advisor. Meanwhile, a mysterious explosion occurs off the coast of Russia sparking nuclear concerns.

Everybody knows that nuclear weapons have been used twice in wartime and with terrible consequences. Often overlooked, however, is the large-scale, postwar use of nuclear weapons: At least eight countries have conducted 2,056 nuclear test explosions, most of which were far larger than the bombs that leveled Hiroshima and Nagasaki.

Russian opacity fuels speculation about a weapons test gone wrong.

Despite official statements to the contrary, the conventionally-armed ballistic and cruise missiles now under development would contribute little to U.S. striking power in a conflict with Russia.