Argument

An expert's point of view on a current event.

Insurgency in Ukraine Could Lead to Major War in Europe

Avoiding escalation with Russia would become even harder.

By , an active-duty Army colonel and assistant professor at the U.S. Army War College.
Ukrainian servicemen patrol the front line.
Ukrainian servicemen patrol the front line.
Ukrainian servicemen patrol in the settlement of Troitske in Ukraine’s Luhansk region near the front line with Russian-backed separatists on Feb. 22. Anatolii Stepanov/AFP via Getty Images

Despite Western military aid and the threat of punishing sanctions that would follow Russian intervention in Ukraine, invasion appears imminent—perhaps to seize the Donbass region or attempt to conquer Ukraine as a whole. Although Ukraine’s military has made major reforms, its ability to deter Russia’s advanced capabilities, numbers, and geographic advantage is limited, and it may find itself quickly overwhelmed.

However, rather than the end of conflict, many analysts—such as FP colleague John Nagl —have suggested this could be just the beginning. Russia is likely to find itself stretched to hold conquered territory and be drawn into the quagmire of insurgency. It’s tempting to think that this would be costly only to Russia, a bleeding wound that deters further adventurism. But such an insurgency is instead likely to lead to even further conflict with the West, whose safe havens and clear anti-Russian support of a Ukrainian resistance would likely lead Russian President Vladimir Putin to further intervention as he struggles to maintain domestic stability in the face of mounting casualties.

A rapid Russian invasion would likely leave many former Ukrainian soldiers as well as civilians in the possession of arms and equipment as well as the motivation to retake their country. Nearby democracies—such as Poland and the Baltics, all recent additions to NATO with long and justified historical reasons to fear Russian aggression—as well as patriotic and romantic histories of guerrilla resistance movements will almost certainly give safe haven to such fighters. Volunteers and the commitment of covert support would soon follow as well, particularly should Ukrainian insurgents acting initially on their own prove themselves capable of drawing Russian blood.

Despite Western military aid and the threat of punishing sanctions that would follow Russian intervention in Ukraine, invasion appears imminent—perhaps to seize the Donbass region or attempt to conquer Ukraine as a whole. Although Ukraine’s military has made major reforms, its ability to deter Russia’s advanced capabilities, numbers, and geographic advantage is limited, and it may find itself quickly overwhelmed.

However, rather than the end of conflict, many analysts—such as FP colleague John Nagl —have suggested this could be just the beginning. Russia is likely to find itself stretched to hold conquered territory and be drawn into the quagmire of insurgency. It’s tempting to think that this would be costly only to Russia, a bleeding wound that deters further adventurism. But such an insurgency is instead likely to lead to even further conflict with the West, whose safe havens and clear anti-Russian support of a Ukrainian resistance would likely lead Russian President Vladimir Putin to further intervention as he struggles to maintain domestic stability in the face of mounting casualties.

A rapid Russian invasion would likely leave many former Ukrainian soldiers as well as civilians in the possession of arms and equipment as well as the motivation to retake their country. Nearby democracies—such as Poland and the Baltics, all recent additions to NATO with long and justified historical reasons to fear Russian aggression—as well as patriotic and romantic histories of guerrilla resistance movements will almost certainly give safe haven to such fighters. Volunteers and the commitment of covert support would soon follow as well, particularly should Ukrainian insurgents acting initially on their own prove themselves capable of drawing Russian blood.

De oppresso liber (“to liberate the oppressed”) is the motto of the U.S. Army Special Forces, originally created to challenge the Soviet Union by fomenting insurgencies inside the Iron Curtain—though instead they ended up fighting one in Southeast Asia. A Ukraine insurgency would be a natural return to their original mission in Eastern Europe—one for which they have always been highly suited. After two decades of fighting insurgencies in Iraq and Afghanistan, NATO’s highly effective and combat-proven special forces would be extremely capable of switching to the task of supporting and prosecuting an insurgency rather than fighting one. This could be in an active role or in the shape of volunteers—whether former or current special operators. But what second- and third-order risks would such an insurgency run?

While so-called hybrid or gray zone conflict may work extremely well for autocracies, such as Russia, it would be far more challenging for Western democracies to manage support for an insurgency on the scale of a potential Ukraine conflict without fairly clear attribution. Hybrid war—which essentially depends on military force in an irregular or nontraditional manner alongside destabilizing information operations—relies on the denial of such attribution. It emphasizes just enough plausible deniability to create a degree of separation from a conflict to present major war.

Because irregular forces—whether insurgent or more formally organized proxy forces, mercenaries, motorcycle gangs, covert special forces, or (occasionally) the concealed use of conventional forces—offer a different optic than traditional military forces, supporting states can deny their use. Alongside these forces, the use of information operations, such as cyberattacks, can be very hard to clearly attribute to particular state actors.

This works quite well in the tightly controlled domestic information environment of autocracies, such as Russia. Yes, the world knows about it, but delaying acknowledgement by the initiating state is enough that carefully defined legal and normative boundaries for interstate war and “not war” are not crossed. However, in the adversarial information environment of Western democracies, whether traditional journalism or informal social media, it’s unlikely the kinds of support necessary for anti-Russian insurgency in Ukraine would not be exposed by independent investigations. The United States found this out with when its attempts to support the Contra insurgency against Nicaragua in the 1980s did not long survive being splashed all over the news. This would be even harder in today’s social media environment, and it would be very difficult to deny active Western participation in an anti-Russian insurgency in Ukraine.

A requirement for successful insurgencies in the modern era has also been the existence of safe havens. The coalitions in Iraq and Afghanistan experienced the challenge of forces that could reconstitute themselves in Syria or Pakistan, just as the Soviets had experienced with mujahideen based out of Pakistan and the United States had experienced with North Vietnamese forces and their proxies operating out of Laos and Cambodia. Such safe havens are critical for insurgents to evade the conventional superiority of counterinsurgents by providing relative freedom of movement, safety for command-and-control elements, and the ability to rest and refit for further operations.

Notably, the cost of avoiding entry to these safe havens is not insurmountable. As the cost of insurgency rises, the barrier to cross-border intervention becomes a risk worth taking to political leaders. U.S. civilian leaders repeatedly denied requests by U.S. military leaders in South Vietnam for cross-border operations to sever the Ho Chi Minh Trail throughout the 1960s. But as costs of the war rose, the Nixon administration finally approved large-scale U.S. and South Vietnamese ground operations into Cambodia in 1970 and a corps-sized South Vietnamese ground incursion into Laos supported by large numbers of U.S. helicopters and jets in 1971—both options considered politically unacceptable due to fear of escalation earlier in the Vietnam conflict.

A successful Ukraine insurgency resulting in mounting Russian casualties would likely provide a similar imperative to eliminate these safe havens. Moscow does not want to see a stream of body bags returning home, which would weaken Putin’s careful hold on domestic stability—always his No. 1 interest. Despite Putin’s considerable control over domestic media, there are limits—and his power relies on maintaining domestic support. Although it would mean taking on even more risks, the danger of losing his grip on power could drive Putin or a future successor to choose such an option. This need not be a direct invasion of the West but could be some other form of loosely veiled direct action against bordering states, such as the Baltic States, Poland, or Romania.

But here is the key difference from previous insurgencies faced by great powers in the modern era—a Ukraine insurgency would almost certainly benefit from safe havens inside the opposing NATO alliance. That’s very different from safe havens in countries that could claim neutrality and are not likely future adversaries for the counterinsurgent power. Cross-border operations into these safe havens in such a case would not simply result in clashes with a minor power—they could instead result in major war. But while this might deter cross-border intervention for a great power whose vital or survival interests are not threatened, an ongoing Ukraine conflict would strike at the heart of Moscow’s perceived interests—both geopolitical and domestic. That might justify extreme risk if it keeps Putin in power.

All of these implications do not mean that ruling out support for an insurgency is a viable option for the West. Decisions to support a future Ukraine insurgency would likely be weighed against the risk of a relatively unchallenged Russia having major combat forces directly on NATO’s doorstep, poised for further action and emboldened by recent success. It would be very difficult to see the NATO border states that are staring down an aggressive Russia denying Ukrainian freedom fighters basic supplies, such as refuge and medical support, and likely much more. The implications are, however, something to carefully consider. The risks would be high for either option.

But as time draws very short to prevent or otherwise restrain a full-blown invasion, these calculations may also provide another potential tool for the West. Putin has almost certainly done this same sort of analysis. He would not want a state-on-state conventional conflict with a united NATO whose military strength significantly outnumbers his own.

Demonstrating resolve and showing Putin that a quick invasion of Ukraine is not only the path to a quagmire of insurgency but a major driver toward an even more damaging future war with NATO might offer another potential talking point to prevent or off-ramp a Ukraine conflict even after it has begun. If such an offramp cannot be secured, the potential costs for Europe are high. And they will only get higher.

Jerad I. Harper is an active-duty Army colonel and assistant professor at the U.S. Army War College who served in Iraq and Afghanistan. These views are his own and do not represent those of the U.S. Defense Department, the U.S. Army, or U.S. Army War College.

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