U.S. President Barack Obama, top, shakes hands with U.S. Army paratroopers assigned to the 173rd Airborne Brigade Combat Team and Estonian soldiers with the Single Scouts Battalion during a troop event for Atlantic Resolve 2014 in Tallinn, Estonia, Sept. 3, 2014. Europe-based U.S. Army units were deployed to Poland, Lithuania, Estonia and Latvia to conduct bilateral military exercises and reinforce NATO security commitments to the host nations.