Russian navy sailors take part in a rehearsal ahead of festive ceremonies commemorating the 75th anniversary of the arrival of the first allied Arctic Convoy, codenamed Operation Dervish, at the northern port of the Soviet Union during World War Two in Arkhangelsk, Russia, August 29, 2016.
Maxim Zmeyev / Reuters

A new arena of competition is opening between Russia and NATO in the North Atlantic. In the Baltic, Black Sea, Ukraine, and even the Middle East, Russia’s geopolitical ambitions have upended all semblance of post-Cold War rapprochement between the two historic adversaries. NATO has built up its military presence along its Eastern flank and revamped its deterrent posture in response. But in its rush to fortify these fronts, it risks overlooking a newly vulnerable Cold War chokepoint known as the GIUK gap.

The GIUK gap denotes the maritime line between Greenland, Iceland, and the United Kingdom that served as a defensive perimeter for NATO during the Cold War. In the event of a war in Europe, the Soviet Union would have to breach the line to cut the United States and Canada off from their European allies. In short, it was the maritime analog to the Fulda Gap.

During the Cold War, the NATO alliance kept a tight surveillance net on the North Atlantic through sea- and land-based aviation, a sustained submarine presence, and a complex web of sound surveillance systems. Since the Soviet threat faded into history, NATO’s focus and presence in the North Atlantic has slipped, eclipsed by complex operations from the Balkans to Libya to Afghanistan. But it cannot ignore the gap’s reemerging importance. And as Russia ramps up its military presence in the North Atlantic, NATO’s presence has atrophied. 

Russia's President Vladimir Putin (L) is seen through the glass of C-Explorer 5 submersible after a dive to see the remains of the naval frigate "Oleg", which sank in the 19th century, in the Gulf of Finland in the Baltic Sea July 15, 2013.
Russia's President Vladimir Putin (L) is seen through the glass of C-Explorer 5 submersible after a dive to see the remains of the naval frigate "Oleg", which sank in the 19th century, in the Gulf of Finland in the Baltic Sea July 15, 2013.
Aleksey Nikolskyi / Reuters
The GIUK gap is still the only point through which Russia can project power into the Atlantic Ocean and Europe’s littoral beyond the bottlenecked Baltic and Black Seas. It remains the gateway to the Atlantic Ocean for Russia’s largest and most strategically important fleet, the Northern Fleet.

NATO does not need to think of the GIUK gap in terms of Cold War-style conventional warfare. However, it must acknowledge that the North Atlantic could be the next focal point for Russian military aggression.

Following Russia’s pattern of actions in recent years, this aggression could take many forms that fall under the threshold of overt conflict, thereby averting NATO and triggering its Article 5 collective defense clause.

One of Russia’s favored methods is violating NATO maritime territory and airspace. Russian warplanes and submarines have skirted or violated the airspace and waters of the Baltic States, United Kingdom, Canada, Denmark, Iceland, Norway, and vital NATO partners Finland and Sweden. Some of these incursions follow routine patterns going back to the days of the Cold War. Some are meant to gather intelligence and surveil NATO’s new military capabilities. But others, such as buzzing the USS Donald Cook, are provocative moves meant to showcase Russian forces to NATO allies. These have exposed embarrassing gaps in NATO members’ defenses.

For example, the United Kingdom had to call on its NATO allies to track a suspected Russian submarine probing its Faslane submarine base (where the backbone of the UK’s nuclear force is located) in January 2015 when it couldn’t muster the ships or planes to track the submarine itself.

Vital global undersea communications cables also run along the ocean floor in the North Atlantic near the GIUK gap, carrying nearly all global internet traffic. Russian submarines have skirted uncomfortably close to the cables in the past in the absence of a U.S. or NATO presence, prompting concerns that the cables would be cut if tensions between Russia and the West worsened over Ukraine, the Baltic States, Syria, or somewhere else. 

The Russian navy frigate Smolny is seen at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, November 25, 2014.
The Russian navy frigate Smolny is seen at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, November 25, 2014.
Stephane Mahe / Reuters
Russia has also begun bolstering its anti-access/area denial (A2/AD) capabilities in the North Atlantic through its submarine capabilities. Through long-range anti-ship and anti-air systems onboard submarines, Russia can create zones in the North Atlantic where NATO planes and ships cannot operate without fear of being shot down or sunk. With a strong enough force in the North Atlantic, Russia could, in effect, cut off North America from Europe.

Russia’s newly unveiled Yasen-class nuclear attack submarine is one of the most advanced, quietest submarines in the world, and it could operate uncontested in the North Atlantic without a strong U.S. and NATO response. During the Cold War, NATO built a sophisticated layer of maritime defense and surveillance networks to block such moves. As the Cold War faded into the past, NATO justifiably drew down its posture in the North Atlantic.

The alliance must now take steps to rebuild and recover its hold on the GIUK gap. Fortunately, this will not require massive investments, new strategies, or significant military reposturing.

First, it must bring the GIUK gap back into the fold of its defense planning, this time with a focus on the GIUK gap–Norway axis as the warming Arctic opens new avenues for military activities. At NATO’s Warsaw Summit, alliance leaders declared that they would “further strengthen [their] maritime posture and comprehensive situational awareness” and “operationalize” the 2011 Alliance Maritime Strategy. NATO planners should factor the GIUK gap into new policy formulations and help their political leaders understand the strategic importance of the North Atlantic to alliance posturing.

Second, NATO should rebuild its basing and surveillance infrastructure in the North Atlantic. The United States took some promising first steps by restoring some routine patrols out of its former naval airbase in Keflavik, Iceland this year after a decade of closure. NATO members should work to permanently reopen certain bases around the North Atlantic to consistently monitor the GIUK gap and strengthen its underwater surveillance systems across the North Atlantic. 

Third, NATO must work to rebuild its members’ maritime patrol aircraft fleets. Maritime patrol aircraft (MPAs) are crucial to tracking Russian submarines and heading off any potential territorial incursions. Many allies mothballed or downsized their fleets due to budget constraints. As countries such as Britain and Norway look to restore their MPA fleets, NATO should consider creating a consortium of alliance-owned MPAs for all allies. This would emulate its successful C-17 and AWACS surveillance aircraft consortiums and help ensure NATO members’ coordination in monitoring the GIUK gap.

Finally, NATO should conduct new military exercises in the North Atlantic with a focus on anti-submarine warfare and coordinating NATO navies and air forces. Military exercises in the North Atlantic would serve the dual purpose of showcasing military strength to Russia and stress-testing NATO’s ability to operate in the open ocean. NATO conducts a small handful of exercises in the North Sea and around the United Kingdom, but it doesn’t conduct any significant military exercises in the North Atlantic. 

A twenty first-century confrontation between NATO and Russia won’t be won in the GIUK gap. However, given its strategic importance, it could be lost there. The GIUK gap is the maritime gate through which the bulk of Russia’s naval power must pass to access the open ocean. Vital global communication linkages run along the North Atlantic, and as Arctic ice recedes, new military and civilian activity in the region will only increase. To sustain security in the region and head off Russian aggression, NATO must take steps to rebuild the defense of this Cold War chokepoint.