From the Document: "As part of our commitment to upholding the principles of the rules-based international order and to the security of our NATO Allies, the United States maintains significant combat-capable forces in Europe. These forward-deployed forces help to deter aggression and if deterrence fails, stand shoulder to shoulder with our Allies to maintain security and stability in Europe. At the President's direction and following Secretary Austin's recommendation, the Department of Defense will reposition certain Europe-based units further east, forward deploy additional U.S.-based units to Europe, and maintain the heightened state of readiness of response forces to meet these commitments. These forces are not going to fight in Ukraine. They are not permanent moves. They respond to current conditions. We will adjust our posture as those conditions evolve, and we will continue to consult closely with NATO Allies to ensure an appropriate collective posture of deterrence and defense."
United States Department of Defense: https://www.defense.gov/