Despite high-stakes diplomacy across not one but two oceans, the Russia-Ukraine War is no closer to ending. In the wake of back-to-back summits involving a host of world leaders, peace seems more distant than ever. Although the United States has threatened penalties if Moscow refuses to make progress toward ending the war, Washington now seems unwilling to crack down on Russia’s prevarication. At the same time, two significant developments that emerged from the summitry—that the United States would participate in providing security guarantees to Ukraine and that Russia would allow Western troops on the ground in Ukraine to guarantee Kyiv’s security—now appear to be less than meets the eye as the US caveats its support and as Moscow claims it too must be involved in Ukraine’s security guarantees.
For months now, European allies have embraced the American effort to forge a peace settlement to end Russia’s war in Ukraine, even as those same allies voiced concern over foisting an unfavorable agreement on Kyiv, and it remained glaringly obvious that Russia showed little sign of budging on its redlines. Eight months into this seemingly futile effort, it’s time for European allies—and ideally the United States as well—to double down on military aid to Ukraine.
There are good operational reasons to do this—Ukraine’s position on the battlefield today isn’t at risk of collapse and in fact is more hopeful than one might assume. More importantly though, there are even better strategic reasons—history tells us that when a stronger power loses a war to a weaker power, the implications can be far-reaching and long-lasting. It also tells us the longer such conflicts last, the better the prospects for the weaker power. For these reasons, the West should not simply aim to prevent a Ukrainian collapse—it should dramatically expand economic and military assistance to Ukraine, regardless of progress in negotiations. Ironically, doing so may be the only way to ultimately achieve a durable peace.
Underdog Under Pressure
Even though a large-scale collapse of the front appears highly unlikely, Ukraine remains at risk of losing to Russia, especially given its manpower challenges. Although estimates of Ukrainian losses vary, most western and independent assessments estimate that Ukraine has lost about 100,000 troops to date, or about half of what Russia has lost. Ukrainian President Volodymyr Zelensky remains reluctant to lower the draft age further, after having dropped it from 27 to 25 in 2024. As a result, the average age of Ukrainian servicemembers is still relatively high at around 43 years old. Given the physical demands of serving at the front line, younger troops predominate there, which means most of Ukraine’s combat losses also skew disproportionately young. This creates a vicious cycle, in turn making it more difficult to recruit and retain younger soldiers. Meanwhile, the United States, Ukraine’s single largest provider of military equipment and related supplies, has backed away from the war, turning over the leadership of aid coordination fora and mechanisms it created three years ago.
However, other indicators appear more promising for Ukraine. For example, non-US military assistance to Ukraine shows little sign of faltering, as indicated by recent announcements of new aid packages, including $500 million provided by Germany through NATO’s new Prioritized Ukraine Requirements List (PURL) initiative. In April, Ukraine’s European allies pledged another €21 billion in military assistance. Some of that funding will be sent directly to Ukrainian defense manufacturers, including those that produce drones like the ones used in the dramatic Operation Spider’s Web earlier this summer. In 2024, Ukraine produced over 1.2 million drones, with production capabilities still rising. This year, Ukraine’s production of uncrewed platforms is expected to exceed that of Russia, reaching as many as 4.5 million. Drones and other uncrewed systems have become increasingly important for both sides, accounting for as many as 70 percent of casualties, and they have facilitated Kyiv’s ability to adapt to evolving Russian battlefield tactics.
Ukraine has also proven resilient in the Black Sea, where Russia has faced a number of setbacks. Despite some early losses in the maritime domain, Ukraine has since utilized asymmetric tactics—such as uncrewed surface vessels and naval mines—to sink over one third of Russia’s Black Sea fleet and half of Russia’s amphibious landing craft in the region, effectively erasing Russia’s pre-war naval advantages.
Moreover, the Ukrainian will remains strong, evidenced by support for Zelensky. Recent polling indicates that roughly two thirds of Ukrainians support Zelensky’s actions as president. Although most Ukrainians are in favor of a ceasefire agreement to end the war, if no deal is reached Ukrainian soldiers appear willing to fight on to ensure the survival of their country. A January 2025 survey found that most Ukrainians oppose territorial concessions. Accounts from those who have recently spent time with Ukrainian military units reinforce the notion that the Ukrainian will has not diminished.
Brute Force, or Bluster?
Meanwhile, Russia clearly maintains a manpower advantage over Ukraine, as well as the ability to outproduce it—and its Western suppliers—in terms of artillery shell production. As a result of these advantages, Russian military forces have made slow but steady territorial gains through most of 2025, despite the Ukrainian adaptation to new Russian tactics and despite the exceedingly high Russian casualty rate. That said, by some estimates, roughly one half of the many thousands of Soviet-era tanks have been destroyed in the war already, and it’s unclear whether the remaining platforms are all combat capable.
Economically, the pre-war challenges of high inflation and low potential for future growth in Russia have only magnified since February 2022. Unlike the West, Russia has placed its economy on a war footing: Military spending accounts for 40 percent of GDP, compared to around 12 percent before the war. In 2023 and 2024, such massive spending levels led to growth rates of between 3.5 and 4 percent. Today though, economic growth spurred by military spending is slowing considerably and is estimated to drop to 0.5 percent in 2025.
Russia has spent much of its vaunted sovereign wealth fund, leading to an inflationary spiral and broader economic challenges. The ruble’s collapse in value prompted the Russian central bank to raise a benchmark interest rate to 21 percent in October 2024, the highest level since the fall of the Soviet Union 35 years ago. Today, the rate remains relatively high at 17 percent. Compounding matters is a worker shortage in Russia’s labor-intensive economy. These economic challenges—including the prospect of even stricter sanctions on the horizon—will make Russia’s war effort in Ukraine increasingly difficult to sustain. In this sense, time isn’t on Moscow’s side.
When Goliath Stumbles
In addition to the operational justifications laid out above for doubling down on aid to Ukraine, there are even more sound strategic, long-term reasons for the West to dramatically bolster Ukraine, reasons that extend far beyond today’s frontline, both geographically and temporally. Although few Western governments may be willing to say so out loud, their actions to date—especially in terms of sanctions, which only have impact over time—point to an implicit recognition that long-term Western strategy toward Russia is best served by weakening the Kremlin relative to the West.
But sanctions may not be sufficient. If, through increased military aid to Ukraine, the West can prevent a Russian victory, history tells us there could be profound implications for Russia’s ability to project power, intimidate and subjugate its neighbors, and threaten Western populations and interests. Weakening Russia would also weaken a key partner of China—Russia’s apparent “partner without limits”—as well as Iran.
In particular, three historical examples illustrate how a loss—or at least the absence of victory—in a war such as that being waged by Russia today can serve to derail a country’s trajectory, sometimes permanently. The first and most obvious historical parallel is the Soviet invasion of Afghanistan. Beginning in December 1979, Moscow sent roughly 80,000 troops to prop up a communist regime that faced increasing pressure from a variety of opposition groups. Over the course of the subsequent decade, the Soviet Union fought a bloody counterinsurgency war against Afghan rebels, who were aided extensively by the United States and others.
Ultimately, approximately 15,000 Soviet troops died in Afghanistan, and another 53,000 are estimated to have been wounded. Given the roughly 4.9 million troops in the Soviet military at the time, this represented a casualty rate of about 1.4 percent. Today, Russia’s casualty rate is far higher in Ukraine, surpassing the combined number of fatalities and wounded of all Russian and Soviet military operations since World War II. Economically, the Soviet-Afghan war proved a drain on Soviet resources, requiring Moscow to quintuple the defense budget and shift significant funds from domestic priorities. In turn, this led to perestroika and glasnost—futile efforts to reform and prop up the Soviet economy. Politically, the war became deeply unpopular in the USSR, and the withdrawal of the Soviet Army—one of the main unifying symbols in the Soviet Union—led to infighting within the Communist Party. Facing economic stagnation and political fragmentation, the government proved unable to respond to growing social discontent. In sum, the war’s massive toll and its second-order effects played a pivotal role in the demise of the Soviet Union in 1991.
In a similar way, the Vietnam War offers a useful example of what can happen after a major power loses a conflict against an ostensibly weaker foe. During the roughly 10-year Vietnam War, the North Vietnamese employed both symmetric and asymmetric strategies, relying on both regular infantry and guerilla warfare, something not yet seen in Ukraine. The United States mobilized a higher percentage of its population to fight in Vietnam than the Russians have done today in Ukraine, yet the Russian casualty figures—in both absolute terms and percent of forces mobilized—already greatly surpass those of the US in Vietnam. The Vietnam War cost the United States roughly $176 billion at the time, which is roughly $1.5 trillion today; in comparison, Russia is estimated to have spent at least $211 billion through February 2025 on the war in Ukraine. More comparable are the figures on defense spending as a percent of GDP. Today, Russia is estimated to spend the equivalent of roughly 7.7 percent of GDP on the military, while the United States spent the equivalent of 7.8 percent of GDP on defense during the Vietnam War years.
Unsurprisingly, Moscow’s war against Ukraine is already generating the kind of economic challenges that confronted the United States during the war and for years after. In particular, Washington’s emphasis on deficit financing of its defense budget helped spur more than a decade of high inflation. More broadly, the American loss against the North Vietnamese led to a decline in American power, draining the US economy and sapping the strength of its military. Arguably the most profound implications were less tangible—the so-called “Vietnam Syndrome” reflected the American public’s aversion to interventions abroad, skepticism toward the use of military power, and general distrust of foreign policy. It wasn’t until the 1991 Gulf War that the United States overcame many of the ghosts of Vietnam.
Finally, although the 1954-1962 Algerian War was one fought to gain independence from France, the conflict shares some similarities with the war in Ukraine today. In both cases, the dominant power faced strong international pressure, while the weaker power amassed international support. The National Liberation Front (FLN) in Algeria gained critical financial backing, military assistance, and political solidarity from China, which sympathized with the anti-colonial cause, and other countries in the developing world such as Egypt. Additionally, in both conflicts the dominant power severely underestimated the strength of the supposedly weaker side, large numbers of civilians (specifically Algerians and Ukrainians) were killed, injured, and/or displaced, and both Paris (in the Algerian War) and Moscow (in its war against Ukraine) denied the sovereignty of their adversaries.
As a result of trying to subjugate the FLN, France significantly increased its defense spending, creating challenges for its economy including sharply increasing its budget deficit and delaying continued implementation of its post-World War II recovery program. This economic instability, coupled with a lack of public support for the French handling of the war, weakened the Fourth Republic irrevocably. Ultimately, the French military failure in Algeria spurred a military coup that ended the Fourth Republic and resulted in General Charles de Gaulle returning to power as president of the Fifth Republic. More broadly, France’s loss meant the end of its colonial empire, prompted a major overhaul of the beleaguered French military, and created rifts in French society that are arguably still not fully healed.
The Longer the War, the Longer Goliath’s Odds
Aside from the three conflicts outlined above, a broader examination of asymmetric conflicts since the 1950s reveals that less powerful states have won a slight majority of them. The reasons for this are complex, including the use of asymmetric strategies in such conflicts, which Ukraine is notably not pursuing, at least not yet.
Critical to weaker state victory though is conflict duration—the longer the conflict lasts, the greater the costs in political, psychological, and material terms for the stronger state both domestically and internationally. At the same time, extended conflict duration often enables the weaker side to adapt strategically and tactically, exploit the stronger actor’s vulnerabilities, and shift the balance in its favor. And when weak actors defeat stronger ones, or at least prevent the stronger ones from achieving victory, there can be profound and lasting effects in economic, demographic, political, and societal terms.
Doubling Down
The West’s best chance of bolstering Kyiv and significantly weakening Russia over time is through a doubling down of Western assistance to Ukraine, even if Washington takes a back seat. Assuming the United States maintains its in-kind intelligence support for Ukraine even as it curtails or ends military, financial, and humanitarian assistance, Europe will need to expand significantly on what it has provided to date.
According to the Kiel Institute, nearly all the roughly $133 billion (€114.6 billion) the United States has provided to Ukraine from late January 2022 through late June 2025 has come in the form of military assistance (56 percent) and financial aid (40 percent). The military support is obviously critical for arming, protecting, and sustaining Ukrainian troops on the battlefield, and here US assistance has averaged $22 billion (€19 billion) annually. Given that European countries have cumulatively provided, on a bilateral basis, just over $27 billion (€23.5 billion) annually to date, they will need to essentially double current levels of military assistance to backfill American aid and thereby keep Ukrainian forces operating at or slightly above their current pace.
The situation is similar regarding financial aid, which is vital for ensuring the Ukrainian government can pay its bills including salaries for troops and civil servants. To date, the United States has provided nearly $16 billion (€13.6 billion) annually in financial aid. European countries have provided, on a bilateral basis, just $3.8 billion (€3.3 billion) annually in financial aid, but collectively—through the European Union—they have provided $20.5 (€17.7 billion) annually. A doubling of this cumulative European financial aid figure—from the current $24.3 billion (€21 billion) to roughly $48 billion (€41.4 billion) annually—would both backfill any reduction in US aid and further strengthen Kyiv’s fiscal situation.
Assuming European countries maintain past levels of annual military and financial assistance, how can they possibly come up with an additional $51 billion (€44 billion) annually? There are four obvious answers. The first involves tapping Russian sovereign debt held in Europe. Euroclear—a Belgian central securities depository—holds an estimated $200 billion (€172 billion) in Russian sovereign assets, while France reportedly holds another $22 billion (€19 billion). Seizing these assets would appear to fulfill Europe’s “doubling down” requirement for more than four years, and it appears Europeans may be increasingly willing to do so. The second option would be to expand and extend the EU’s Ukraine Facility for financial aid beyond its current $54 billion (€50 billion) cap through 2027. The third option would be to leverage Germany’s newfound willingness to borrow based in part on its relatively low debt-to-GDP ratio—it is virtually alone among major European economies in having the fiscal “headroom” to take on additional debt. And finally, some leading European countries such as France, Italy, and Spain—which face virtually no territorial security threats—have the potential to significantly expand in-kind military assistance to Ukraine. Unlike allies farther east, these southern tier allies have scope to do more.
Of course, Kyiv needs to do its part as well, principally by strengthening its manpower resources. Although Russian casualties have been staggering, Moscow still maintains a manpower advantage over Ukraine. To mitigate this, Kyiv should both lower the conscription age further, to 23, and expand enlistment incentives for those not compelled by law to join. Doing so will be politically difficult for Kyiv, but dramatically expanded Western aid will signal a long-term commitment to Ukraine’s security and could go far in easing the political challenges.
Preventing a Russian victory by tying Moscow down in a quagmire of the Kremlin’s making is likely to continue to deplete Russian resources, inhibit Moscow’s ability to horizontally escalate elsewhere in Europe, weaken Putin’s position domestically, erode a key partner of China (and Iran), and undermine Russia’s long-term ability to threaten Western interests.
N.B. The views expressed are the authors’.
John R. Deni is a research professor at the US Army War College’s Strategic Studies Institute, a nonresident senior fellow at the Atlantic Council, and a nonresident senior fellow at the NATO Defense College.
Elisabeth Nielsen is an undergraduate student majoring in International Relations and Public Policy at the College of William & Mary, where she is also the co-president of the William & Mary Global Innovation Challenge (WMGIC).
