New CNAS Analysis on the Risks of Russian Opportunistic Aggression in Europe

Washington, September 4, 2025 — The Center for a New American Security (CNAS) released a new report today, Understanding Russia’s Calculus on Opportunistic Aggression in Europe by authors Andrea Kendall-Taylor, Jim Townsend, Kate Johnston, and Greg Weaver. The report analyzes the gaps in European security that would emerge if the United States reduced its forces in European theater—either as a result of crisis in the Indo-Pacific or as a deliberate policy choice.

In the case of a crisis over Taiwan, the United States may be forced to rapidly shift resources to the Indo-Pacific. While many of the resources required to defend Taiwan are different than those required for European continental security, the report finds that key capabilities—including intelligence, surveillance, and reconnaissance (ISR) platforms; strategic enablers; ground-based air and missile defense; and long-range precision fires—could be redeployed, threatening European deterrence.

The report finds that Russian President Vladimir Putin could view the absence of certain U.S. capabilities as his last best chance to undermine NATO, judging that Washington would have neither the political interest nor the resources to rapidly come to Europe’s defense, and that absent the U.S. capabilities being redeployed to the Indo-Pacific, the European members of NATO would be vulnerable. The greater the gaps and vulnerabilities in NATO’s conventional forces that Russia perceives, the greater the risk Moscow is likely to accept in pressing its ambitions.

The authors assess that Moscow is likely to assume that, with hostilities in Asia, the imperative for the United States and Europe would be to de-escalate, creating a context that the Kremlin would view as exceptionally permissive. A shortage of U.S. ISR capabilities in Europe would, for example, degrade NATO’s situational awareness of Russian activity and early warning, leaving the alliance more vulnerable to missing Russian hybrid attacks.

Beyond hybrid actions, U.S. involvement in the Indo-Pacific would also heighten the risk of a kinetic Russian action against a NATO member state. Moscow could come to judge that the absence of key U.S. capabilities would slow a NATO response, giving Russia time enough to seize territory and then use coercion to compel NATO to accept the result.

“There is no guarantee that Putin would directly challenge NATO, but there is a risk that he could try—and one that would grow significantly if the United States were engaged in a conflict in the Indo-Pacific,” write the authors. “It is critical now that the United States and Europe take practical actions to mitigate that risk.”

For more information or to arrange an interview with the report’s author, please contact Charles Horn at [email protected].