In the wake of the NATO summit at The Hague, doubts over America’s commitment to European security will persist. Ultimately, this is what US disengagement looks like. Europeans must adapt to this new reality and take greater responsibility for their own defence.

European militaries are facing the twin challenges of a hostile geopolitical environment and the global energy transition. There are solutions to fuel and electricity dependencies: prioritising biofuels and infrastructure in the short term while developing synthetic fuels, and...