Designing New Battlegroups: Advice for NATO Planners

“If Kremlin’s aim is to have less NATO on Russia’s borders, it will only get more NATO.” As NATO’s secretary general Jens Stoltenberg points out, one consequence of Russia’s war of aggression in Ukraine is now clear: President Putin will end up with more NATO on his borders, not less. It looks increasingly likely that both Finland and Sweden will join NATO soon—possibly before the alliance’s critical Madrid summit in June. More immediately, the quantity of NATO’s forces deployed on its eastern flank is multiplying rapidly.

NATO originally deployed its “enhanced forward presence” (EFP) of four combat-ready battlegroups in 2017, in response to Russia’s 2014 occupation of Ukraine. Following Russia’s full-scale invasion in February, these missions in Estonia, Latvia, Lithuania, and Poland have now all doubled in size. In parallel, the activation of its response force also put 40,000 troops in the region under direct NATO command.

At a recent extraordinary leaders’ summit, Stoltenberg also announced NATO will double the number of EFP missions to eight, with new battlegroups going to Slovakia, Hungary, Romania, and Bulgaria to “reinforce Allied deterrence and defence” in the region. To date, NATO has released little detail regarding the composition of its new battlegroups. As NATO military planners develop these new forces, here are five principles that should guide their work:

1. Be Clear about the Strategic Objectives

First, be clear about what forces are there to achieve. Short of changing facts on the ground through brute force, the utility of military presence is to support and create space for wider political and diplomatic efforts. There are three likely strategic goals for NATO’s new battlegroups: reassurance, deterrence, and compellence.

Allies closer to Russia are more susceptible to hostile actions given their proximity and history. NATO’s presence in these frontline states reassures them other nations have its back—there are currently troops from 17 of the 30 NATO nations in the three Baltic states—and assures them of the sanctity of the Article 5 commitment to their collective defense. Reassuring allies requires demonstrating both resolve and capability, so any new measures must signal both clear political support and sufficient military hardware. These deployments are requested by the host nations, who define the size and shape of the forces they host to reassure their own populations: too small and the effect is lost, too large and they might feel unduly threatened or lose confidence in their own government’s ability to keep them safe.

This dynamic also applies to the deterrent effect on Russia: too small may embolden, while too large may provoke. NATO’s EFP deployments seek to deter in part by acting as “tripwires” that would trigger, in the event of aggression, a collective response with substantial follow-on forces. While NATO’s flexible posture illustrates the proportionate and defensive nature of these measures, some studies point to the shortfalls of this model of “deterrence by reinforcement” and call for a more robust approach of “forward defense.” Studies of deterrence suggest being as specific as possible in linking military threats to unwanted behavior. One challenge is the difficulty of deterring hybrid threats in the “gray zone” short of war.

Russia’s behavior may require adding another strategic aim to NATO’s forward presence: compellence. The distinction between deterrence and compellence is more than semantic: it is the difference between preventing an action versus stopping or undoing it. If President Putin’s actions are viewed properly as the latest in an established pattern of regional revisionism and brinksmanship, stopping them requires moving from deterrence to compellence. However, the historical record shows using military force to compel is more difficult than deterrence—not least for psychological reasons such as loss of face (although this can be tempered with skillful diplomacy and the use of “carrots” as well as “sticks”).

2. Exploit a Wide Range of Force Posture Variables

A second principle is to use the full range of force elements available. With access to the military forces of 30 nations—and nearly 60% of global defense spending—NATO has a wide range of military and nonmilitary tools at its disposal to tailor any new presence to the strategic effects sought.

One variable is the composition of forces, which can range from small-footprint training missions to heavy deployments capable of high-end warfighting. There is some flexibility here. For example, because reassurance is a product of both resolve and capability, high-resolve/low-capability deployments (such as local “tripwire” forces) can have similar overall effects to low-resolve/high-capability deployments (such as heavier forces stationed offshore).

Further flexibility can be found in the type of forces and operating domains. Land forces provide traditional “boots on the ground” and a visible presence among local populations. They can also enhance the credibility of deterrence through bringing to bear the heavy ground forces required to defend, seize, and hold territory in the event of conflict. Air forces can provide specific roles such as air policing, surveillance, and enforcing no-fly zones. For example, one study of Estonian airspace violations highlights the role of quick-reaction jets in deterring sub-conventional aggression. Although their role is limited by geography, naval forces offer perhaps the widest range of options, including: maritime security, freedom of navigation, high-end aircraft carriers (of which NATO currently has five in the area – see map), amphibious forces, and long-range missiles.

NATO’s resources also go far beyond conventional military forces. Many allies have developed sophisticated capabilities in strategic communications and information operations. The same goes for cyber defense, where NATO is able to deploy rapid reaction teams and run cyber operations from its own cyber command. Some allies have developed sophisticated offensive cyber capabilities. NATO has also developed counter hybrid warfare teams, which have already deployed to Montenegro and Lithuania. All of these tools can be brought to bear as part of NATO’s forward presence.

3. Location, Location, Location

An important consideration for new forward presence missions is where to base them. NATO planners have three options: bolster existing missions, develop missions that have already been floated in public, or introduce entirely new missions.

One advantage of adding to existing presence—such as the EFP missions in Estonia, Lithuania, Latvia, and Poland, or NATO’s five regional air policing missions—is the ability to use established infrastructure and status-of-forces agreements. The political and public support required to rotate allied forces through the host nation is also already in place. The downside is the relative effect: new missions in new places may create a greater impact in the minds of local populations and adversaries than simply adding to existing ones.

New missions on the table include the four new battlegroups in Slovakia, Hungary, Romania, and Bulgaria. Official information on their composition remains thin. The most detailed proposal put forward by NATO is the “enhanced vigilance activity” battlegroup in Romania, led by France. Also known as the “Eagle Mission,” the immediate purpose of this 800-personnel strong battlegroup is to reassure the Romanian population of NATO’s commitment to its defense and deter Russian military maneuvers through enhanced situational awareness—in other words, deterrence by detection or disclosure. But this force may need to evolve in its posture as it transitions to a more persistent presence, especially if it wants to deter (by denial or punishment) or compel.

One approach with more coercive potential would be to wrap the significant U.S. presence in Romania, alongside other allied forces, under the new French-led EFP mission. More broadly, the Black Sea region is home to three NATO members (Romania, Bulgaria, and Turkey), two partner nations (Ukraine and Georgia), and a growing appetite for a bigger allied presence. As Romanian president Klaus Iohannis has said: "I have repeatedly pleaded for a more consistent presence of NATO, the United States and other allies in the Black Sea region." Many commentators—including NATO’s secretary general—have called for a more strategic approach to NATO’s presence in the Black Sea region. Given its geography, the allied presence, and its importance to Russia, there are plenty of options for NATO to increase its presence and influence in the region, especially at sea—but these must be explored carefully as most nations in the region need to balance their relations between Russia and NATO.

4. Use the Whole Toolbox

NATO’s forward presence missions are not the only tool it has to reassure its allies and deter and compel Russia from further aggression. One tool of deterrence is multinational exercises—such as the massive Norwegian-led exercise Cold Response held during March and April—which can be used to signal capability and solidarity, while reassuring partners. Other tools include high-readiness and reinforcement forces, such as NATO’s Response Force and its Very High Readiness Joint Task Force (VJTF), which can be used to signal NATO’s ability and willingness to deploy combat forces to defend its allies and deter aggression.

NATO also works with partners outside the alliance to demonstrate solidarity and reassurance. Doing so also complicates the adversary’s decisionmaking as they are forced to include NATO-third party relationships in their calculus. Cooperation with partners also has other benefits, such as investments through EU mechanisms in logistics and infrastructure to facilitate military mobility across the Euro-Atlantic area.

More broadly, continuing to increase defense investment and modernization—in particular on the high-end forces critical to gaining credible deterrence—will also be essential to building the credibility of NATO’s overall defense and deterrence posture. Allies had already increased collective defense spending by $270 billion since the 2014 Wales summit even before many of them committed to going further than the 2% of GDP target in response to Russia’s invasion. Investing in a credible nuclear posture within NATO by modernizing nuclear forces—including those involved in the alliance’s nuclear sharing agreements—will also be instrumental to deterrence. This involves responding to Russia’s own nuclear provocations—including through NATO nuclear exercises, which would remind Russia, as well as allied domestic populations, of NATO’s own nuclear might.

5. Anticipate Russia’s Response

The final piece of the planning puzzle is to consider how Russia might respond to these moves and feed any insights back into planning. Despite NATO’s insistence, it has not convinced Russia of the alliance’s defensive character. Russian officials repeatedly have described NATO as an inherently anti-Russian institution whose aim is to contain the country. Such rhetoric has intensified since the start of the war in Ukraine.

In this context, an increase in NATO force posture or exercise tempo would likely be perceived as an escalatory gesture, although the size, scope, and intent of these measures could influence Russia’s reaction. One study on deterring Russia concluded that light ground forces deployed in potential target counties were associated with a higher risk of escalation due to Russia’s redlines, meaning that NATO’s preferred approach of small-scale forces in “frontline” nations could be counterproductive. However, the same study concluded that “heavy ground forces . . . stationed in nearby countries, but not in the potential target countries themselves, are most clearly associated with deterrence.”

Even with losses approaching a quarter of its fighting force in Ukraine, Russia’s existing defensive capabilities may be sufficient to handle even a considerable increase in NATO  forces in eastern Europe. However, Russia’s reaction to a shift in NATO force posture may not be symmetrical. Russia’s confidence in its nuclear capabilities and its investments in strategic nonnuclear assets suggest that it may counter NATO’s actions indirectly. This might include equipping land-based and maritime forces in the Black Sea region with additional cruise missiles or deploying nuclear-capable Iskander ballistic missile batteries closer to the borders of NATO allies.

An asymmetric Russian response would also include “gray zone” or “hybrid” aggression. For example, following the initial EFP deployments in 2016, disinformation specialists detected a surge in false and divisive narratives about NATO and its presence. This time, planners in Brussels should develop and resource a counter-disinformation strategy, building on the signaling by NATO leaders that these new missions “remain preventive, proportionate and non-escalatory.” The same goes for cyber defense and societal resilience support to the host nations, building on NATO’s work on resilience under Article 3 of the Washington Treaty.

Finally, given the volatility of the current strategic environment, NATO planners should also work on ways to maintain, if not reinforce, military-to-military channels of communication with Russia. With an increasing military presence from both sides, such channels, combined with risk-reduction mechanisms, are vital to avoid unintended escalation.

Busy Times for NATO Military Planners

NATO’s military planners should consider these five key principles when designing its enhanced forward presence in eastern Europe. Yet, NATO’s four new battlegroups are just the beginning of its “reset” for the longer term. As the current debate within NATO between “forward presence” and “forward defense” moves on toward its historic Madrid summit and new Strategic Concept in June, these new missions could be just the tip of the iceberg of forces that could end up in President Putin’s backyard as a result of his decisions. However far NATO’s “reset” goes, these principles should guide NATO’s military planners—who will be busy for the foreseeable future.

Sean Monaghan is a visiting fellow in the Europe, Russia, and Eurasia Program at the Center for Strategic and International Studies in Washington, D.C. Andrew Lohsen is a fellow in the Europe, Russia, and Eurasia Program at CSIS. Pierre Morcos is a visiting fellow in the Europe, Russia, and Eurasia Program at CSIS.

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