The imposition of U.S. tariffs on China in April 2025 prompted China to restrict rare earth exports, affecting global supply chains. The U.S. and Israel’s strikes on Iran expanded the battlefield to Gulf states. These events highlight the growing tactic of horizontal escalation used by major powers like China, Iran, and Russia to challenge U.S. influence.
Horizontal Escalation Explained
Horizontal escalation involves spreading conflicts into new geographical regions or areas of competition. This approach challenges the U.S., which typically organizes its strategies into distinct categories such as NATO, trade policy, and Taiwan. Meanwhile, adversaries operate across these boundaries, aiming to transform the existing international order.
Collaboration Between Adversaries
China, Russia, and Iran have different capabilities and objectives but often share a common goal of destabilizing the U.S.-led global order. Instances of cooperation are evident. Tehran has provided Moscow with drone technology, while Russia assists Iran’s military advancements, including developing supersonic missiles. Additionally, China supports both nations by supplying dual-use items and purchasing sanctioned oil.
Resilience as a Strategy
Each nation’s efforts drain American resources needed elsewhere, exposing vulnerabilities. U.S. alliances amplify its strength but also present more targets to adversaries. To counter horizontal escalation, the U.S. and allies must make it difficult for adversaries to exploit opportunities. Strategies include diversifying vulnerabilities, hardening essential areas, and stockpiling military capabilities. Allies should also take on more responsibilities.
Implementing Horizontal Escalation
Horizontal escalation options should be developed by the U.S. and its allies. Russian sabotage should incur penalties in areas valuable to Russia, like supporting Ukraine and limiting Russian financial activities. Consequences should not only affect direct areas of pressure but should extend beyond.
Germany’s response to incidents like the Leipzig explosive-laden drone attack embodies this approach. Germany increased defense support to Ukraine, showcasing how threats can lead to strategic responses. Similar strategies should be applied to interactions with China and Iran, where economic actions might trigger responses in different domains.
Building Stronger Alliances
Horizontal escalation can unintentionally strengthen U.S. alliances. Adversarial actions may unite disparate partners under common causes. When China retaliated by disrupting European supply chains, the U.S. formed a critical minerals partnership with Europe. Such dynamics encourage Gulf states and Asian allies to reassess their ties with Beijing and Moscow.
To effectively manage horizontal escalation, coordination among allies is crucial—guarding against sabotage and coercion, sharing deterrence responsibilities, and collaborating on protecting key technologies and supply chains. American leadership remains pivotal in using openness as a strength rather than a weakness.
Peter Rough, Director of the Center on Europe and Eurasia at Hudson Institute, emphasizes that the U.S. and its allies must demonstrate the capability to adapt and apply the tactic of horizontal escalation.