The Marine Corps is a very tough and flexible force.

But perhaps the most versatile Marine unit is the Marine Corps Security Force Regiment — a dedicated security and counter-terrorism unit that’s used for everything from guarding nukes to rescuing diplomats.

In fact, the more famous counter-terror units like Delta Force, SEAL Team Six, the Special Air Service, or GSG 9 are young whippersnappers compared to the Marine Corps Security Force Regiment. Tracing its lineage to the 1920s, the Marine Security Force Regiment was around long before the SAS was a gleam in the eye of David Stirling.

Marine Corps’ Security Force Regiment
Marines engage an armed objective during a room-clearing exercise at Advanced Interior Tactics training aboard Naval Support Activity Northwest Annex in Chesapeake, VA, December 7. During the course, Marines were taught to identify the hands of an individual to determine whether or not they posed a threat, in order to control the scene and conduct thorough house clearings. (Photo by Sgt. Kayla D. Rivera/USMC)

When the Navy’s part of America’s nuclear triad is in port, it’s these Marines that defend it.

The Security Forces Marines get the task for one simple reason: America’s SSBN force may be safe when it’s out at sea, but when in port, it is vulnerable to attack. Not only that, the UGM-133 Trident II ballistic missiles are usually not on the submarines and represent a perfect target for those seeking to cripple the sea-based deterrent.

Part of that effort includes the unit’s Recapture Tactics Teams. According to Military.com, these teams specialize in recovering materials, people, and property tied to the strategic inventory.

AmericanSpecialOps.com notes that they are called the close-quarters combat (CQB) Team, and they are trained to act at the squad level.

According to its official webpage, the Security Force Regiment is also tasked with providing “forward-deployed, expeditionary antiterrorism and security forces to support designated commanders and protect vital national assets” and “expeditionary antiterrorism and security forces, deployable from the United States, to establish or augment security as directed by the commander of U.S. Marine Corps Forces Command.”