The low implied probabilities on US withdrawal from NATO markets reflect major procedural barriers, including the 2023 statutory requirement for congressional authorization via supermajority Senate vote or separate legislation before any formal notice under the North Atlantic Treaty. The Trump administration has pursued retrenchment through a Pentagon review of European force posture, with options due shortly after the November 2026 midterms and final results expected in December, following earlier modest steps such as the withdrawal of several thousand troops from Germany and reduced commitments of US assets to NATO contingencies. European allies have signaled readiness to assume greater security responsibilities, while diplomats monitor whether midterm outcomes could accelerate troop reductions or funding adjustments to appeal to domestic priorities. No official denunciation has occurred, and scheduled events like the review completion remain the primary near-term catalysts that could influence trader assessments.