In September of 2011, the U.S. Navy’s Second Fleet was stood down after 65 years of patrolling and defending the northern Atlantic and America’s East Coast. Most of its personnel were absorbed into U.S. Fleet Forces Command as a part of a restructuring that aimed to reduce costs in the face of ongoing anti-terror campaigns around the world.

That decision, like the decision to bring Lockheed Martin’s F-22 program to a halt, has since begun to look a bit short-sighted, as American lawmakers seemed so focused on the war America was fighting that they lost sight of historic opponents. Now, with tensions between the United States and Russia at their highest since the Cold War, America’s defense apparatus has had to reassess the way it does business — starting with the return of the U.S. Navy’s Second Fleet.

Our national defense strategy makes clear that we’re back in an era of great power competition as the security environment continues to grow more challenging and complex,” Chief of Naval Operations Adm. John Richardson said on Friday. “That’s why today, we’re standing up 2nd Fleet to address these changes, particularly in the North Atlantic.”

Prior to Second Fleet’s 2011 stand down, it served primary in humanitarian aid and drug interdiction efforts, as that portion of territory, comprised of both sovereign American as well as international waters, was not seen as a contested territory. However, since Russia’s military annexation of Crimea in 2014, concerns about Moscow’s aggressive behavior have stirred a reawakening of Cold War concerns — concerns that proved valid as Russian activity began to increase in the Atlantic.

In March, Russian media reported that a number of Russian nuclear attack submarines had successfully infiltrated American defenses, closing to within miles of U.S. Navy installations along the Eastern seaboard before returning to Russian territory. Those claims have not been addressed by U.S. Defense officials, likely because if it did happen, they may not have been aware, and if it didn’t happen, the U.S. would have to expose elements of its submarine detection methodology in order to counter their claims.

Russian submarine Severodvinsk | Russian MOD

In either case, the threat is no longer simply perceived — Russia has made it clear that they see America as not only a diplomatic opponent, but conceivably a target. This understanding is made all the more disconcerting with the recent revelation that a Russian weapon once believed to be a matter of propagandized fiction is actually a reality: the Status 6 100 megaton nuclear submersible drone.

Naval Forces Europe commander Adm. James Foggo III wrote in the U.S. Naval Institute’s publication, Proceedings,

Russian submarines are prowling the Atlantic, testing our defenses, confronting our command of the seas, and preparing the complex underwater battlespace to give them an edge in any future conflict,” Naval Forces Europe commander Adm. James Foggo III wrote in the U.S. Naval Institute’s publication, Proceedings.