Can Europe Compensate for Dwindling U.S. Support to Ukraine?

It's a mixed bag.

We don’t yet know exactly how U.S. policy toward Ukraine will evolve under the incoming President Trump and his new Administration.

While the worst-case scenario—where the United States completely cuts off Ukraine from additional aid—is by no means the most likely scenario, there is a good chance that Trump will reduce the level of support for Ukraine or use it as a bargaining chip with Europe.

The implications of this will vary across different areas, with Europe better positioned to compensate in some respects than in others. The following presents a short discussion of where Europe is relatively better and worse placed to step in. While not constituting a comprehensive analysis, it can provide some pointers for how Europe can approach the Trump Administration in an effort to future-proof military assistance to Ukraine.

Where Europe can compensate

Europe’s military production remains significantly below where it should be, even two and a half years into a war on European soil that is, in many ways, existential for its states. That said, there have been notable improvements in certain areas.

A standout example is the production of 155mm artillery shells, which has benefited from substantial investment and expansion efforts. Official reports from March this year estimated an annual production capacity of one million shells. However, independent analysis, likely more accurate, suggested that by March 2024, the EU had reached a production capacity of 550,000 shells.

Despite this uncertainty, the European Union and its member states have consistently allocated funds to enhance production capabilities—not only for the shells themselves but also for critical components such as explosive filler—to meet the demands of the current security environment. While production levels still fall short of the necessary targets, there is a clear commitment to scaling up capacity. Two million shells annually by mid-2025 is absolutely a realistic objective.

It’s no secret that losing access to American artillery shells would constitute a significant challenge. However, this is likely the one area where Europeans have a genuine opportunity to independently supply Ukraine with what it needs, provided there are further expansion efforts and national rearmament efforts assume a secondary priority. Given that 155 mm artillery shells are critical to Ukraine’s warfighting efforts, Europe’s ability to supply the AFU in this area can be taken as an encouraging sign.

Where Europe cannot compensate

In other areas, Europe will not be able to compensate for the loss of American assistance, particularly in long-range strike weapons, air and missile defense interceptors, and rocket artillery munitions.

Europe has, in all its wisdom, failed to increase the production of one of the most critical weapon systems for 21st-century warfare: long-range strike weapons. While the United Kingdom, France, and Italy have delivered quite substantial numbers of Storm Shadow/SCALP-EG cruise missiles, these stockpiles are now severely depleted. France’s recent delivery of only 10 SCALP-EG missiles highlights the extent to which European states are running on empty in this domain.

The only Western nations maintaining substantial stockpiles of long-range strike weapons are the United States and South Korea. However, South Korea has refrained from providing direct military assistance to Ukraine, largely due to its need to preserve missile capabilities for conventional and nuclear warfighting contingencies on the Korean Peninsula. This leaves the United States as the sole realistic supplier of such systems.

If U.S. support is withdrawn, and considering that Europe has made no meaningful effort to scale relevant industries since February 2022, the prospect of Ukraine acquiring a substantial number of cruise and/or ballistic missile systems effectively vanishes.

Moreover, the United States remains the sole supplier of rocket artillery launcher systems and munitions. Without continuous efforts to backfill Ukraine’s arsenal from European GMLRS stocks (which are rather low themselves), Ukraine would simply exhaust its existing arsenal with no real alternative on the horizon.

The situation is arguably most dire in missile defense. While several European states have contributed capabilities—notably France with SAMP/T and Germany with IRIS-T SLM—Ukraine remains heavily dependent on the United States, particularly for ballistic missile defense.

Ukraine’s primary means of countering Russian ballistic missile attacks relies on Patriot missile defense batteries. While other systems, such as Soviet-legacy S-300V systems and the Franco-Italian SAMP/T, are available, the scarcity of interceptor munitions and the limited number of launchers and radars prevents these systems from effectively substituting for Patriot.

Without U.S. assistance, Ukrainian cities and critical infrastructure would become severely vulnerable to ballistic missile strikes. Ukraine’s ability to defend against cruise missile and long-range drone attacks would also take a major hit, given that NASAMS interceptors would also no longer be delivered.

What to do

It is unlikely that the United States would completely cut off Ukrainian access to American weapon systems, regardless of how determined President Trump might be to withdraw support for Ukraine. Trump has a penchant for emphasizing financial deals, and the American defense industrial lobby is likely too strong and influential to permit such a move—fortunately, in this case.

This means weapons would remain available for purchase, either by European states for transfer to Ukraine or directly by Ukraine itself. However, this would come at a high cost, one that Europe and Ukraine may struggle to afford.

The best option remains convincing Trump that abandoning Ukraine would damage his image, portraying him as weak and ineffective.

Nonetheless, Europe should prepare concessions to offer Trump to prevent a complete withdrawal. In the worst case, this might include directly compensating the United States for certain weapon deliveries, potentially at a discounted rate.

European leaders must also push President Biden to immediately invest every available dollar from the Presidential Drawdown Authority and other funding mechanisms, particularly in areas vulnerable to disruption under Trump, such as ballistic missile defense.

Finally, while the ideal time for Europe to dramatically increase arms production was February 2022, the second-best time is now. Outside of a few areas, such as 155mm shells, Europe has largely failed to scale its defense-industrial base. But let’s be crystal clear: Europe’s defense sector is no longer capable of being "Trump-proofed," at least not in the short term. This represents a significant policy failure, as decision-makers had years to address this vulnerability but failed to act decisively—or, in some areas, to act at all.