The secret Pentagon command that tried to plant a fake bomb in D.C.

The Joint Special Operations Command has become one of the most important cogs in the U.S. war machine.

Known as JSOC, it is part of the Department of Defense. It oversees the army’s elite Delta Force fighters, the Navy Seals and a fleet of drones. It has played a major role in the U.S. response to 9/11 — and in every theater of the Global War on Terror: Afghanistan, Iraq, Somalia, now Syria.

But where did it come from? How has it grown? And what role does it play in the fight against ISIS? We turn to Sean Naylor, author of a new book, “Relentless Strike: the Secret History of Joint Special Operations Command.

P.J. Tobia interviewed Naylor for this week’s Shortwave.