US troop reductions and a Pentagon review of European force posture, set to conclude by December 2026, reflect the Trump administration’s push for greater European burden-sharing and a pivot toward the Indo-Pacific. Officials have signaled frustration with some allies over defense spending and support during recent operations, prompting selective exclusion from NATO working groups and calls for a “NATO 3.0” model with Europe assuming conventional leadership. A 2023 statute requires congressional approval for treaty withdrawal, and a new bipartisan bill would add further procedural hurdles. Administration statements continue to affirm no intent to exit the alliance outright, though sustained drawdowns of thousands of personnel and assets could test alliance cohesion without triggering formal departure.