Lingering territorial disputes—particularly around the heavily Russian-occupied Donbas region—still have to be resolved.U.S. President Donald Trump meets with Ukrainian President Volodymyr Zelenskyy at Mar-a-Lago in Palm Beach, Fla., on Dec. 28, 2025. Joe Raedle/Getty Images12/28/2025|Updated: 12/28/2025U.S. President Donald Trump welcomed Ukrainian President Volodymyr Zelenskyy...