The US faces significant structural barriers to full NATO withdrawal, including the 2023 Kaine-Rubio statute requiring congressional authorization before any president can exit the treaty. Recent developments include ongoing Pentagon reviews of force posture in Europe, expected to conclude by December 2026, alongside announced reductions such as 5,000 troops from Germany and cuts to assigned fighter jets, bombers, and naval assets. Tensions have risen over European allies' limited support during the Iran conflict, prompting public questions from administration officials about alliance commitments and burden-sharing. European members have increased defense spending while exploring alternatives to US equipment. Traders weigh these force adjustments and diplomatic pressure against the high threshold for formal exit and institutional pushback from Congress and defense stakeholders.