NATO’s in denial about deterrence by denial

John R. Deni is a research professor at the U.S. Army War College’s Strategic Studies Institute, a nonresident senior fellow at the Atlantic Council, and an associate fellow at the NATO Defense College. He’s the author of “NATO and Article 5.” The views expressed are his own.

Recent revelations that the Chinese government has been substantially aiding Russia’s war effort in Ukraine — selling the country all it needs to build its own armaments, including microchips for drones and missiles, machine tools and explosives precursors — have renewed debate in the West over how quickly Moscow will be able to reconstitute its land power.

Not long ago, conventional wisdom held that the losses sustained by Russia’s ground forces through 2022 to 2023 were substantial enough to require several years of rebuilding. Casualties in the hundreds of thousands and the loss of two-thirds of its massive tank force led many to reason Russia was down and out — at least in the short run. The only disagreement seemed to be over how many years it would take to rebuild.

Ironically, this discussion of timelines seems irrelevant to those closest to the threat. Government officials from Estonia, Finland, Latvia, Lithuania and Poland view Russian President Vladimir Putin as utterly opportunistic, unwilling to wait for some subjective measure of readiness before launching his next attack. Hence, what matters more than the West’s prognostications are the Kremlin’s perceptions of Western resolve, capability and capacity. 

So, with doubts now sown over America’s willingness to reinforce its NATO allies in case of a Russian attack, the organization’s best bet in the increasingly risky context of European security is to implement a “deterrence by denial” strategy — aiming to stop and repel an attempted attack on allied territory without giving much, if any, ground. And truth is, the alliance is already halfway there — at its Madrid summit in 2022, NATO committed to pursuing deterrence by denial. Unfortunately, the reality along the Eastern flank doesn’t yet match this rhetoric.

Despite widely known shortcomings in allied capacity, however, achieving this type of deterrence is actually possible. And by reversing its decisions on conscription, expanding and refining its force structure in Eastern Europe, and modifying its approach toward Russia’s aggression in the air and the electromagnetic spectrum, NATO could take the necessary steps during its Washington summit this summer.

Deterrence by denial is a strategy that sounds intuitively appealing — and something NATO should be capable of. However, over most of its history, the alliance has struggled to achieve it.

For example, during the Cold War, NATO occasionally came close to matching Warsaw Pact countries’ conventional military strength along the border between the then two halves of Germany, but it was usually undermatched. And this inability — or unwillingness — to achieve conventional force parity in part reflected the West’s pursuit of deterrence on the cheap in contrast to the Soviet Union.

Then, following the end of the Cold War, this conventional force imbalance vis-à-vis Russia became even more dramatic. But this was tolerable for two reasons: First, to many in the West, Russia simply wasn’t as aggressive — or, judging from its numerous failed military reform efforts, as effective — as it appeared in Soviet times. Hence, there was strong public support for a peace dividend, slashing conventional strength and dropping conscription. Second, the kinds of operations allies were increasingly conducting — like those in Kosovo and Afghanistan — demanded more highly trained, mobile professional forces.

So, this inability to achieve deterrence by denial led the alliance to pursue deterrence by punishment — a form of deterrence aimed at convincing potential aggressors that NATO will strike back in devastating fashion if attacked. However, since deterrence by punishment can’t prevent an aggressor’s early gains, the clear — if often unstated — implication is that territory may be lost, at least initially.

And NATO has pursued this approach in defense of its most vulnerable members — the three Baltic states and Poland — since 2014. For example, since 2017, NATO has stationed one multinational Enhanced Forward Presence (EFP) battle group in each country. These units were initially relatively small — around 1,200 troops each — and they were comprised of forces from across the alliance, which meant that if Russia attacked, it would be taking on troops from nearly all of NATO.

Of course, the downsides of these small multinational units were that they lacked the heft necessary to blunt and repel an initial invasion, and they suffered serious interoperability challenges. However, given the lack of consensus among allies on Russia’s intent, and the unmistakably strong deterrent signal of allied solidarity, these and other operational shortcomings were deemed reasonable risks.

After Russia’s second invasion of Ukraine in February 2022 and the ensuing brutal war, though, NATO reexamined its approach and took several steps to strengthen its efforts. | Kenzo Tribouillard/AFP via Getty Images

After Russia’s second invasion of Ukraine in February 2022 and the ensuing brutal war, though, NATO reexamined its approach and took several steps to strengthen its efforts.

It completed new allied operations plans, which based allied defense planning, exercises and force sizing more closely on real-world threats. It revamped its force structure, embracing a new NATO Force Model designed to provide larger numbers of troops at higher readiness, and placed multinational battle groups in Slovakia, Hungary, Romania and Bulgaria. It also moved to integrate its new members — Finland and Sweden — remarkably quickly. And given these changes, the alliance has now begun modifying its command structure as well. It has also agreed to expand its small battle groups to brigade-size, when and where necessary.

But none of this adds up to deterrence by denial. Allied efforts to create tripwires on land, air, sea, cyberspace and the electromagnetic spectrum have been — and remain — inadequate. To be clear, the alliance deserves praise for what it’s done to date, but with an unpredictable leader in the Kremlin, none of it’s sufficient to achieve deterrence by denial.

This won’t be an easy or quick fix either, but it is possible — and there are policy moves NATO should embrace, such as personnel expansion, force posture changes and modified rules of engagement, in order to do so.

Regarding personnel, NATO simply needs more. Nearly all major European allies — especially France, Italy, Germany and the U.K. — face military personnel shortages. Decisions made a decade ago to invest in capabilities at the expense of capacity mean that even as these allies have become increasingly capable of fighting side-by-side with their American counterparts, they’ve been fielding smaller militaries. And even those with plans to expand personnel, like Germany, don’t have plans to resource them.

So, how many more troops does NATO need? Deterrence by denial doesn’t necessarily mean matching Russian forces soldier-for-soldier everywhere — although NATO would be better off aiming for parity in the territory of its most vulnerable allies. Attacking is usually considered a “harder” military task than defending. It requires troops to leave the safety of fortifications and enter unfamiliar “foreign terrain,” so typically a three-to-one ratio is necessary for offensive success. To mitigate this, NATO should aim to prevent its forces in the east from falling below a two-to-one or 1.5-to-one ratio.

Overall, this means more European allies will likely need to reexamine their decisions to ditch conscription, as well as embrace more robust development and activation of reserve forces to help allies achieve the necessary mass. Larger European NATO countries, which have the populations to support bigger military formations, will be critical here. And with Germany at least beginning to discuss conscription, NATO should give its endorsement at the Washington summit.

Then, on posture, NATO needs to beef up its forces in the east — and not just “where and when required.” The alliance needs to build up its forces both qualitatively — especially to counter specific Russian offensive capabilities in indirect fires and electronic warfare — and quantitatively, to meet the scale of the Russian threat.

In terms of quality, this means endowing NATO’s forward military units with more full-spectrum capabilities, including electronic warfare, unmanned aerial vehicles, short range air defense and cyber. And in terms of quantity, it means that each forward military unit in the three Baltic states, Poland and Romania ought to be made into brigade-size units permanently. The German-led unit in Lithuania is headed in this direction, and the Canadian-led unit in Latvia may be as well — but the timelines for this are woefully long.

As for reducing the interoperability frictions in some forward military units — the one in Latvia, for example, suffers from this the most, with 10 contributing allies — a country’s minimum contribution to each unit ought to be a battalion. Meanwhile, there’s no reason to have land-centric forward military units in Slovakia, Hungary or Bulgaria, as these allies face no significant ground threat. And given the threats facing Romania, NATO should convert the unit there into its first Multi-Domain Task Force, with an emphasis on intelligence, maritime domain awareness, air defense, and long-range artillery and rockets.

Finally, allies need to shift their approach when it comes to Russia’s aggression in the air and the electromagnetic spectrum.

In the air domain, some have framed this as a move from air policing to air defense but, in any case, the goal should be to forcibly end Russian aircraft and missile incursions into allied airspace. For instance, the NATO countries should announce they’ll no longer tolerate violations of allied airspace by piloted Russian aircraft, flyovers of any ally by Ukraine-bound Russian missiles and rockets, or Russian drone activity within a certain distance of the alliance’s eastern frontier.

To make good on this, NATO should then forward station-appropriate integrated air and missile defense assets along its eastern front, starting in southeastern Poland and northeastern Romania — something that may also have the unintended benefit of creating no-fly zones over portions of western and southwestern Ukraine.

As for the electromagnetic spectrum, it’s become increasingly clear that Russia’s aggressive, indiscriminate use of electronic jamming isn’t just threatening military operations by allied forces in NATO’s east but, more worryingly, civilian aviation and maritime activity. Will the allies wait until Russia’s electronic warfare downs a civilian airliner before they respond?

Taking the necessary steps to fully operationalize deterrence by denial now is critical — especially before a possible change in America’s relationship with NATO. And this upcoming Washington summit provides the ideal opportunity for NATO to finally embrace this strategy.