At the outset of the invasion, the odds favored Russia to defeat the Ukrainian armed forces, seize Ukraine’s capital, and establish a pro-Russian government. The Russian military comfortably outnumbered Ukraine’s, and its military technology was more advanced. Russia’s GDP was nearly ten times the size of the Ukrainian economy, and its population about triple that of its neighbor’s. Many analysts expected that, after being largely conquered, Ukrainians would launch a protracted insurgency that might defeat the Russians over time. But few believed Ukraine could stop the invasion in a conventional war.   

And yet Ukraine has held on. Russia’s assault on Kyiv stalled within a month and failed entirely shortly thereafter. Moscow did not topple the Ukrainian government, and its invasion was halted not just around Kyiv but also along the southwestern coast. Russia has withdrawn its battered forces from around the capital and from large swaths of northeastern Ukraine, covering its defeat with claims that it was simply refocusing its efforts to the Donbas. Russian troops have made more progress in this region but only slowly and at the cost of many casualties. The Russian invasion grinds on, but Kyiv and other swaths of Ukraine will be free when it finally ends.

Russia’s invasion has come up short for many reasons. Ukrainian heroism and remarkably intelligent and adaptive fighting techniques are major ones. Russia’s failure to prepare for serious Ukrainian resistance and, therefore, to develop supply systems that could support a prolonged assault on northern Ukraine is another. But none of these factors—alone or together—explain Russia’s stunning failure to achieve its initial objectives. Instead, analysts must consider a problem for Russia that is far more fundamental: its invasion plan itself was shockingly bad.

Successful military campaigns usually follow several central principles. Military leaders must choose the most important objective and then assign the right amount and right kind of military forces to ensure its achievement. Rather than trying to do everything at once, they must prioritize and sequence operations to make achieving this objective as easy as possible. And they must design campaigns to make sure that they will bring the combat power necessary to win the war’s last battle and to attain their political objectives.

Russia’s invasion plan was shockingly bad.

Russia knows these principles well. Indeed, the Soviet Union perfected many of them over the course of decades, and the post-Soviet Russian military inherited and further developed these doctrines to conduct large-scale mechanized warfare. But in Ukraine, it violated every one of them. Russia’s invasion was sweeping and unprioritized rather than sequential and deliberate. It mismatched its forces to tasks and gave Ukraine’s defenders clear ways to fight back. In fact, Russia’s design choice was so poor that the invasion would have likely failed even if the supply arrangements had been sound. 

Russia may yet win the next phase of the war. Its military leadership seems to be learning from its logistics problems in its new campaign in eastern Ukraine. It can concentrate more forces on a smaller area. Its overall reserves of manpower and equipment, although surprisingly depleted, remain larger than Ukraine’s. But Russia’s military leadership seems not to have rediscovered how to follow proper campaign design principles, a fact that is already compromising its renewed offensive. It may again lead to failure.


The initial Russian objective was to seize Kyiv and other major Ukrainian cities, remove the current Ukrainian government, and impose a new regime beholden to Moscow. Russia’s first and overwhelming objective, then, should have been taking the capital, and a sound campaign plan would have prioritized this aim and subordinated actions elsewhere. The collapse of the Ukrainian government and the destruction of the Ukrainian military forces defending it, after all, would likely have unhinged Ukrainian defenses elsewhere, making the conquest of eastern and southern Ukraine much easier.

But that’s not what Russia did. Instead, it also set out to secure the territory of Luhansk and Donetsk regions, known as oblasts, for the Moscow-controlled Luhansk and Donetsk’s “People’s Republics,” and it tried to establish a land bridge connecting the northern Crimean Peninsula with Russia itself. Russia did attack south from Belarus and its own territory toward Kyiv with large forces, but it also sent a large contingent of troops to seize the city of Kharkiv (which is 250 miles to the east), another large force to drive into Luhansk oblast even farther east, still another to seize Mariupol, and a final large concentration to take Kherson, Mykolaiv, and ultimately Odessa—all at the same time. In short, the Russians made the mistake of trying to conquer everything they wanted in Ukraine simultaneously. 

Conquering Kyiv was entrusted to Moscow’s least-trained and worst-equipped mechanized forces.

Russian forces would have attacked in the south and east even in a well-designed campaign, but for a different purpose. Their aim should have been to trap Ukrainian forces in fights in those areas to prevent them from rushing to Kyiv and interfering with the decisive battle. To accomplish that objective, Russia’s initial attacks in the south and east should have used much smaller forces and pursued much more limited territorial objectives than they did in reality; doing so would have allowed the Russian military to concentrate its best troops and the most combat power on the difficult task of seizing the capital. Instead, Russia assigned its premier armored force—the 1st Guards Tank Army, which is optimized for a rapid offensive using tanks and armored personnel carriers—to attack the eastern city of Sumy, about 190 miles from Kyiv. Conquering Kyiv was then entrusted to the troops of the Eastern Military District, the one with the least-trained and worst-equipped mechanized forces.

Russia might still have seized Kyiv if it had been able to reinforce the Eastern Military District with good troops. A soundly designed campaign (one consistent with Soviet and Russian military theory and doctrine) would have kept some forces in reserve for precisely such a purpose. But the Russian military committed all its available forces trying to achieve all its objectives simultaneously, leaving no meaningful reserve. When the drive on Kyiv bogged down, the Russians had to cast around for whatever reinforcements they could find. They compounded their error by rushing those reinforcements piecemeal into the fight, rather than pausing to cohere effective groupings, fueling tactical failures that led to Russia’s final defeat outside the capital.

Russian operations elsewhere in Ukraine replicated these flaws. Southern Military District forces in Crimea attacked at once along three diverging axes—to the west toward Kherson and Mykolaiv, with the intention of continuing on to Odessa; to the east toward Mariupol; and to the north toward Zaporizhzhia. These attacks did not support one another—separate groups of Ukrainian troops defended Kherson and Mykolaiv, Mariupol, and Zaporizhzhia, and so attacks in one direction did not threaten Ukrainian defenders in the others. And splitting Russia’s forces deprived all three axes of the strength they needed to truly achieve their objectives. Russian troops took Kherson relatively quickly, but they failed to take Mykolaiv or find another way toward Odessa. The offensive toward Zaporizhzhia was halted about 40 miles south of the city. Russia eventually seized most of Mariupol, but only at a horrific cost. Had the Southern Military District focused on each campaign sequentially, it might have made much more rapid and significant progress.


After having failed in the north and across much of the south, Russia has begun a new phase of the war focused on capturing the east while holding on to the parts of southern Ukraine and the Kharkiv region it has already taken. Moscow has concentrated its remaining forces for attacks along four main axes in the Donbas—from Izyum to the southeast; from the area around Rubizhne to the west; from Popasna to the west; and from Donetsk to the north. The fifth large concentration of Russian forces has just declared victory in Mariupol, although fighting continues. Some of those forces have already begun moving north to join the fight in the western Donbas while others try to finish securing Mariupol.

But so far, the apparent design of this campaign appears to share important flaws with Russia’s initial operation. For one thing, it again seeks to achieve all of Russia’s objectives simultaneously: seizing the entirety of Donetsk and Luhansk oblasts, as well as the rest of Mariupol, in a single campaign in the next few weeks. For another, Russia is operating along multiple axes of advance that are not mutually supportive. Separate groups of Ukrainian forces defend against each axis, and the Russian attacks are too far apart for any combination of them to threaten the same Ukrainian troops (at least for now). Finally, the Russians are committing all available forces to the fight from the outset. They do not appear to be retaining mobile reserves to reinforce advances that stall.

This Russian campaign does have important advantages over the initial invasion. It is occurring in a smaller area, one that allows Russia to fight against a part of Ukraine’s military rather than spreading its forces out against the whole of the Ukrainian armed forces. The four major axes of advance are also roughly along the radius of a semicircle that stretches from Izyum to Donetsk, which means if Russian forces can make enough quick progress, their attacks will become complementary as they converge.

George Barros / Institute for the Study of War

But it remains unclear if the Russian military sees these advantages, if it seeks to use them, or if it can. The natural path for Russian forces looking to encircle Ukrainian troops in the pocket around Popasna, Rubizhne, and Severodonetsk would be to advance from Izyum southeast toward Slovyansk, and from the area around Russian-occupied Debaltseve northwest along the same highway to Slovyansk. But although Russian forces around Izyum have been trying to drive toward Slovyansk, they have somewhat oddly begun pushing out to the west, away from the rest of the Russian forces operating in the Donbas rather than toward them. On the southern arc of the semicircle, Russia has thus far not sought to drive northeast from Debaltseve—possibly because of difficult terrain and stubborn Ukrainian defenders—and has instead launched an attack from Donetsk north through Avdiivka. This route is superficially more attractive than routes closer to Debaltseve because it leads through more open countryside. But it is about 30 miles west of the Slovyansk-Debaltseve highway, and it could require Russian forces to cross 50 to 100 miles of Ukrainian defenders without the support of other Russian attacks.

Ultimately, these errors may not be decisive. Strategy isn’t everything, and the real strength and combat power of Russian forces may matter more than the geometry of planned advances. Conversely, Russia could correct these mistakes in their campaign planning and still fall short: the fact that the Russians are trying to remedy their critical logistical flaws, for example, does not mean they will succeed in doing so. There are plenty of other factors that will also help shape the outcome, including the flow of Western equipment to Ukraine and the ability of the country’s exhausted defenders to keep resisting Russian advances.

But for now, the current Russian campaign plan resembles the initial invasion plan in a microcosm, and it will likely suffer from many similar problems. It suggests that the Russians have truly forgotten everything they and their Soviet predecessors ever knew about how to fight mechanized warfare on a large scale. And it means that, despite being outgunned, the Ukrainians have a real chance.

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  • FREDERICK W. KAGAN is Senior Fellow and Director of the Critical Threats Project at the American Enterprise Institute.
  • MASON CLARK is Senior Analyst and Russia Team Lead at the Institute for the Study of War.
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