How Ukraine Can Win Through Defense

A New Strategy Can Protect Kyiv and Stop Moscow From Winning

On December 12, Ukrainian President Volodymyr Zelensky traveled to Washington to make an in-person request for military and economic aid for Ukraine, but he left empty-handed. For over a month, Republicans on Capitol Hill have been blocking an emergency spending bill that would provide about $60 billion in new funding for Ukraine. They will approve the money, they have vowed, only if Democrats make major concessions on immigration policy. Until then, funding for Ukraine remains in the balance.

Zelensky’s disappointing visit highlights the larger problems facing Ukraine. Its much-anticipated counteroffensive last year failed to retake territory lost to Russia, public support for Kyiv across the West is declining, and the conflict is at a stalemate. At the same time, the dilemma for Western policymakers appears stark. They can continue to pour resources into the war in search of an increasingly improbable version of victory: retaking every inch of Ukrainian territory. Or they can cut funding, put Kyiv on the defensive, and risk a Ukrainian loss. This striking dichotomy is no doubt the reason that the Biden administration publicly insists there will be no change in strategy if Congress doesn’t approve funding. But there is in fact another option, one that is being largely overlooked in Washington: victory through defense.

Much of the aid to Ukraine over the last two years has focused on offensive capabilities—advanced Western tanks, mine-clearing equipment, and long-range missiles—in a bid to push Russia back. But victory for Kyiv and its Western partners does not necessarily require gaining back specific chunks of territory. It simply requires that Russian President Vladimir Putin be denied his goal of subjugating Ukraine.

If Ukraine can defend the territory it controls in the coming months by using capabilities such as antitank mines and concrete fortifications, it can deny Russia a path to complete victory and perhaps even open the door for negotiations. Putin evidently believes that time is on his side; a strong, sustainable Ukrainian defense would prove him wrong.

The current predicament facing Western policymakers is the result of maximalist thinking. On one side of the debate are those who argue that Ukraine cannot be victorious until it retakes every square ­­­­­­­­­­inch of its territory, including the seven percent of its land that Russia has held since 2014. This could be called the “victory through rollback” argument. As Ben Hodges, the former commander of U.S. Army Europe, put it: “Victory for Ukraine means total restoration of all their sovereign territory,” including Crimea. On the other side are those who argue that the United States has spent too much already and that Ukraine should sue for peace now, in a traditional “peace, not victory” approach. “There are appropriate ways in which the U.S. can support the Ukrainian people, but unlimited arms supplies in support of an endless war is not one of them,” 19 Senate and House Republicans wrote in a letter to the White House last year, adding, “Our national interests, and those of the Ukrainian people, are best served by incentivizing the negotiations that are urgently needed to bring this conflict to a resolution.”

Neither of these options is good. There are genuine constraints on what the West can provide Ukraine to enable it to retake territory. Public opinion in the United States and Europe is turning against significant additional funding, and stockpiles of Western ammunition are running low. Ukraine made few concrete gains on the ground last year even with massive amounts of Western support and advanced weaponry. None of the equipment that Ukraine is now asking for, including a longer-range version of the Army Tactical Mission System (ATACMS) or F-16 fighte­­­­r jets, is likely to change that reality in the coming year. That said, it is not an ideal time to seek peace negotiations, either. Despite the apparent stalemate on the battlefield, it is unlikely Putin would agree to a cease-fire until after the 2024 U.S. presidential election, which he surely hopes will deliver him a Trump presidency and thus a better deal. He is also undoubtedly aware of the grim math of land warfare: Russia has a larger military-age population to draw from than Ukraine and a stronger industrial base. On paper, time is on his side.

Policymakers in the West know they need a new strategy: the White House is increasingly pushing Ukraine to pivot to a defensive strategy in 2024, and Zelensky and his military commanders have slowly come to accept the need for this shift, announcing in November an expansion of defensive fortifications. Yet U.S. policymakers also need a new theory of victory. A pivot to defense is the right idea, but both Washington and Kyiv are pursuing it for the wrong reasons. On both sides of the Atlantic, defense is viewed largely as a stopgap measure to buy time to build capacity for future offensive operations. As Jack Watling wrote in Foreign Affairs recently, the West “faces a crucial choice right now: support Ukraine so that its leaders can defend their territory and prepare for a 2025 offensive or cede an irrecoverable advantage to Russia.” Similar views seem to hold in Kyiv, where defense seems to be viewed as a necessary evil that needs to be done while the military focuses on building up its reserve forces and continuing its deep-strike campaign against Russian logistics. General Valery Zaluzhny, commander in chief of Ukraine’s armed forces, argued recently that “new, innovative approaches” could still turn the tide of the war. In both cases, the plan would see Ukraine rebuild its forces this year and resume counterattacks no later than in the spring of 2025.

Policymakers in the West know they need a new strategy.
So far, however, these theories of victory have failed the battlefield test. Neither Kyiv’s maneuver warfare campaign, in which Ukrainian forces attempted to break through Russian lines and quickly recapture territory, nor its attempts to undermine Russian popular support for the war through drone attacks on Moscow have succeeded. Putin is nowhere closer to conceding defeat because he still believes his army has a viable path to victory. He thinks he can outlast Western support for Kyiv and eventually defeat Ukraine through sheer attrition.

Even after two years of war, Putin’s exact objectives are unclear. The initial assault in February 2022 clearly aimed to decapitate and subjugate the Ukrainian state. When that failed, the Kremlin indicated that it sought the full conquest of four Ukrainian regions: Donetsk, Luhansk, Kherson, and Zaporizhiya. At a strategic level, however, Putin’s political objectives are relatively clear: weaken Kyiv, seize as much territory as possible, and prevent Ukraine from further integration with Europe.

Defense, then, can itself be a path to victory if Ukraine and its Western backers can succeed in convincing Putin that there is no way for him to achieve these strategic objectives. Under this approach, Ukraine would build strong fortifications and defensive capabilities to demonstrate that the country can sustain a long war of attrition and prevent further Russian advances, even with reduced Western support. Over time, a consistent, sustainable Ukrainian defense could eventually convince the Kremlin that continued fighting is futile, opening the prospect of peace.

If there is one clear lesson to draw from this war, it is that today’s battlefield favors defense. Modern weapons, especially drones, advanced artillery, and long-range antitank missiles, make it much easier to hold territory than to capture it. Mobile ground-based air defenses are hard to detect and destroy, giving defenders an advantage over modern air forces. A shift to defense in Ukraine would capitalize on these advantages and would require three specific elements to be successful.

First, Ukraine would need to construct a system of defensive lines consisting of deep trenches, prepared firing positions, ditches, antitank mines, and the concrete antitank pyramid barriers known as “dragon’s teeth”—a system not unlike the so-called Surovikin Line of fortifications that Russian forces so successfully defended last year. Ukrainian troops already have the right mantra: “If you want to live, dig.” Yet Ukraine’s defenses to date have consisted mainly of shallow trenches rather than fixed fortifications, as the military has waged a mobile defense, launching hit-and-run attacks on Russian forces and supply lines.

Defenses must also be thick and layered, progressively sapping Russia’s military power should its forces dare cross them. The first line should be densely mined with antitank munitions and concrete barriers, behind which Ukrainian troops in bunkers and trenches would lie in wait with murderous firepower. The second defensive line, an insurance against a breakthrough, would offer more of the same, exacting a heavy price on any Russian attackers. These defensive works would offer Ukrainian troops significantly more protection and allow them to better withstand Russian offensive action than the mobile defense it has fought until now.

This could be surprisingly cheap to achieve. For example, Russia built its dragon’s teeth for about $130 for each pyramid, laying around 1,000 concrete pyramids in four rows to fortify just under a mile of front. At that cost, Ukraine could fortify the entirety of the Donbas front lines (about 260 miles) for about $54 million. Antitank mines are cheap, too, at a cost of less than $10,000 each, and the U.S. military has many of them, including over 178,000 M21 mines slated to soon be replaced by new models. Though mines carry the potential for civilian harm even after a conflict is over, in this case, the benefits outweigh the risks. The United States should not only contribute the mines but also work with its allies to plan for risk mitigation and future de-mining operations.

Second, Ukraine should prioritize keeping the skies contested, ensuring that neither side enjoys air superiority. Although Ukrainian commanders insist that even small numbers of Western fighter jets such as the F-16 would be enough to gain air superiority over the battlefield, that seems highly unlikely. Russian radar would spot these planes well before Ukrainian pilots came within weapons range to destroy Russian air defenses, especially the country’s S-400 missile systems.

As Ukraine has already shown in this war, however, it can succeed on defense as long as its ground-based air defenses remain a credible threat to Russian warplanes. Today, Western antiair missile stockpiles are running low, raising the risk that Kyiv will no longer be able to hold back the Russian air force. To avoid this prospect, Ukraine may need to make the unenviable choice to be more selective in employing its air defense capabilities. This may mean that its forces cannot attempt to intercept every Russian missile or drone fired into Ukraine, which would increase the potential for civilian casualties. Yet if Kyiv continues to try to shield its population rather than its air defenses, the country risks losing the air war. The West may be hard pressed to meet Ukraine’s current air defense needs, but this is one area in which creative thinking can help: the launch of the FrankenSAM project, which aims to marry advanced Western missiles with Ukraine’s Soviet-era launchers and radar, offers one path toward addressing this critical shortage.

Third, Ukraine must expand its domestic weapons production, reducing its reliance on Western arms supplies. During the Cold War, Ukraine was a major arms manufacturer, and Kyiv’s efforts to ramp up defense manufacturing since the start of the war show promise. The number of Ukrainian companies producing drones, for example, has increased from seven to 80 in the last year. Other countries will be wary of sharing sensitive military technology, but much of what Ukraine needs for defense—artillery, drones, and antitank weapons—are cheaper, less sensitive, and relatively easy to produce. A more self-reliant Ukraine would signal to Moscow that even if Western support for Ukraine diminishes, Russian troops will face stiff military resistance.

A shift to defense is valuable not only because it could show the Kremlin that further territorial conquest is out of reach but also because it would help Ukraine address its two biggest problems: a shortage of soldiers and flagging Western support. A network of strong defenses would allow Kyiv to husband its resources, reducing the number of personnel and amount of artillery required to defend its frontlines. With a serious conscription crisis brewing in Ukraine, any strategy that requires fewer troops is a clear winner.

Going on the defense is also cheaper for Kyiv’s Western backers. A defensive strategy alleviates the need to arm Ukraine with expensive and scarce Western systems meant to give it a qualitative offensive edge, such as advanced fighter jets or tanks. Instead, the West could reorient aid around lower-cost munitions, construction supplies, and air defense systems while working to ramp up Ukraine’s defense industrial base.

To shore up flagging Western support, however, it will not be enough to simply pivot to defense on the battlefield. If Western leaders continue to emphasize Ukraine’s winning back its territory yet struggle to pass massive new aid packages, Russia can maintain hope that Western funding will falter and the Kremlin’s prospects will improve.

Therefore, a new battlefield strategy must be accompanied by a corresponding political strategy from the White House, beginning with messaging. The Biden administration should make clear that it is not seeking to support Kyiv with future offensive operations but is rather focused on providing Ukraine with defensive capabilities. The message from the White House should be simple: Ukraine stands a better chance of holding on to its existing territory and sustaining the fight with a defensive playbook.

To make this strategy credible in Moscow, the White House would also need to engage in signaling. Rather than continuing the high-stakes push on Capitol Hill for a mammoth Ukraine aid bill, the White House should seek a smaller, compromise budget to fund less expensive defensive systems for Ukraine and help the country build its own defense industrial base. Money is perhaps the most obvious outward indicator of strategy. By dialing down its funding request, the White House can signal it has adopted achievable strategic goals: a cheaper war is a far more sustainable war.

The White House can also broadcast its intentions by applying pressure on Kyiv. Indeed, a central obstacle to this new strategy will likely be opposition in Ukraine itself. Ukrainian leaders may oppose a shift to defense, as it could lead to the war’s ending along current lines of control, similar to what happened at the end of the Korean War. Although that conflict never officially ended, the fortification and stabilization of the 38th parallel eventually produced a durable armistice that allowed South Korea to flourish. A defensive strategy in Ukraine might ultimately produce a similar outcome—and the White House should make clear that it would consider this a victory. Indeed, if there is one thing that would qualify as a loss for Putin in the long term, it would be a flourishing, independent Ukraine that is economically integrated with Europe.

A cheaper war is a far more sustainable war.
Finally, the Biden administration will need to build Western consensus around this new approach. This strategy should be appealing to European countries that are suffering their own shortfalls in public support for the war, including Germany. But it will be a much harder sell in eastern Europe, where victory through rollback is popular. A common fear in Poland and the Baltic states is that any failure to reclaim all of Ukraine’s territory will send a message to the Kremlin that future aggression may be rewarded. To address these concerns, the Biden administration should lean not just on the idea that a defensive strategy is cheaper but also on the argument that it could be effective in preventing further Russian gains in Ukraine, making conquest elsewhere in Europe less attractive to Moscow. Such a stance can also help reassure allies: a defensive strategy is significantly more resilient to shifts within the Western coalition, future-proofing Ukraine’s defense against volatile U.S. politics.

If Congress falters in providing funding for Ukraine in 2024—or if Donald Trump is reelected president—European states are far better positioned to provide defensive supplies than offensive weapons. Even basic construction materials—concrete, for example—are useful in creating fortifications; the German concrete industry has been hit hard by higher energy prices. Both German companies and Ukrainian forces would benefit from German government spending on material for fortifications.

Ultimately, a defensive strategy will not solve all of Ukraine’s problems. No matter what approach the country takes, it will almost certainly face another brutal winter of Russian drone and missile attacks on its energy infrastructure. And of course, a defensive strategy requires Kyiv to abandon its maximalist goals of retaking all the territory it has lost to Russia. That means leaving the Ukrainians living in the occupied territories under Russian rule, a costly and wrenching choice even when the prospects for retaking this territory are so slim.

But if executed well, a defensive political and military strategy may well be able to persuade Putin that he has no prospects for further conquest in Ukraine, creating an off-ramp for negotiations. And even if this new strategy does not end the war, it will avoid the most catastrophic outcomes, will sustain Ukraine’s fighting capacity, and just might produce a stable equilibrium that allows a largely intact Ukraine to develop economically and integrate with Europe. For Western policymakers feeling stuck between domestic constraints and the prospects of a Ukrainian loss, that should count as a win.

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