The number of American troops in Europe has risen sharply in the four months since Russia invaded Ukraine, jumping from about 65,000 in mid-February to 100,000 today.
But that increase, one of the most rapid U.S. military build-ups on the continent in the post-Cold War era, comes without a clear end date or any obvious metrics to determine when troops could come home or be repositioned to other key theaters such as the Indo-Pacific.
Instead, their mission is to deter further Russian aggression and prevent any attack on NATO territory — a goal that will prove difficult to measure and one that could potentially justify a years-long mission as Russia and Ukraine settle into a slow, bloody war of attrition in the Donbas.