By wielding different navies' aircraft carriers, NATO is showing off an 'easy to miss lever' of combat power

• Three times this year, NATO has assumed command of members' aircraft carriers for exercises.
• The drills have been meant to practice integrating national forces under alliance command.

Three times this year, NATO has assumed command of member navies' aircraft carriers to practice integrating national forces under alliance leadership, an often-overlooked capability that experts and officials say is vital for NATO to operate effectively in wartime.

In late January, Naval Striking and Support Forces NATO took command of the USS Harry S. Truman carrier strike group from the US Navy's Italy-based Sixth Fleet as part of the NATO-led exercise Neptune Strike 2022.

That handover "demonstrates the power and cohesiveness of our maritime forces and the NATO alliance," Vice Adm. Gene Black, who commands both Sixth Fleet and Naval Striking and Support Forces NATO, said at the time.

In mid-May, Black's NATO command again assumed control of the Truman strike group as part of Neptune Shield 2022, which focused on "overcoming the complexities of integrating command and control," according to a release.

At the end of May, Naval Striking and Support Forces NATO also assumed command of Italian aircraft carrier ITS Cavour and its strike group, a first for NATO, as part of Neptune Shield.

Integrating with Cavour "removes artificial seams between the maritime and air domains," said British Royal Navy Rear Adm. James Morley, deputy commander of Naval Striking and Support Forces NATO.

The exercises were what NATO called "vigilance activities," which US Air Force Gen. Tod Wolters, the Supreme Allied Commander in Europe, said "strengthen our ability to seamlessly integrate maritime strike capabilities to support deterrence and defence."

Naval Striking and Support Forces NATO is unique in that it provides "a separate, direct line of control" from Wolters' command to specific strategic forces, usually carrier strike groups, said Joshua Tallis, a research scientist at CNA, a Virginia-based research and analysis organization.

That allows Wolters "to maneuver those high-value units across the theater as a nimble and responsive force in a way that is largely unparalleled" elsewhere in NATO, Tallis, an expert on naval operations, told Insider.

The exercises were also part of Project Neptune, which began in early 2021 with the goal of defining the process through which Sixth Fleet and Naval Striking and Support Forces NATO would handle the transition of warships between national and NATO command.

Project Neptune activities have strengthened the "resilient, multinational command structure" that is "a critical but easy-to-miss lever of NATO's combat power," Tallis told Insider.

Integrating air, sea, and land operations is challenging and depends on "unflashy staff work that can be easy to neglect," Tallis said, adding that such work is harder in the NATO context, in which 30 members have to work with each other and with the alliance's command structure.

When command-and-control of US Navy ships shifts to NATO, "back-end staff work" that is critical to that integration "shifts to a different group of people in a different building in a different country," Tallis said. "Doing that well is not a given — hence the value in these demonstrations."

Mastering complexity, building cohesion

Amid heightened tensions with Russia over the past decade, NATO navies have reemphasized being present and capable of operating around Europe, especially in hotspots like the Black Sea. NATO also set up its newest operational-level command, the Virginia-based Joint Forces Command Norfolk, in 2018 to ensure that the waters between Europe and North America stay open.

The national- and NATO-level interest in improving integration has been evident in recent exercises, many of which prominently featured aircraft carriers.

Ships and aircraft from NATO allies accompanied new Royal Navy aircraft carrier HMS Queen Elizabeth on its maiden deployment in 2021 and joined the French-led exercise Polaris, which centered on the aircraft carrier Charles de Gaulle, late last year.

"Increasingly, NATO allies are expanding their high-end maritime warfighting capabilities by integrating into exercises and carrier strike group deployments," the US Navy said ahead of the Polaris exercise.

In February, Truman and Cavour trained with de Gaulle in the Mediterranean to improve "their capacity to work as a cohesive team in defense of national and allied interests," the US Navy said.

In March, HMS Queen Elizabeth's sister ship, HMS Prince of Wales — which took over as NATO's command ship in January — led naval forces during Cold Response 2022, the largest military exercise hosted by Norway since the Cold War.

Russia's attack on Ukraine in late February has added to tensions in Europe and complicated life for NATO navies.

Truman remained in the eastern Mediterranean in the weeks prior to Russia's attack to reassure allies and, after the invasion began, to support alliance members with aerial patrols over Eastern Europe.

At the start of the war, Russian warships shadowed US and French carriers in the Mediterranean, Adm. Pierre Vandier, French Navy chief of staff, said in May. The Russian ships included cruisers, frigates, and submarines, "so it was a very complex environment," Vandier said.

When Moscow's intentions in Ukraine became clear, work being done for Project Neptune "served as a logical focal point for NATO alliance cohesion and signaling activities" and facilitated "calibrated demonstrations of strength," Tallis told Insider.

The project has also highlighted the value of mastering the complexity of "rapidly shifting a large force package," like a carrier strike group, at an especially tense moment, Tallis said. "That capability, and its political implications, have only taken on more urgency in the last three months."