A potential demilitarized zone in Ukraine would be unfeasible as long as Russian troops continue to operate in Ukraine, U.S. State Department spokesperson Matthew Miller said on Feb. 1. Miller was responding to a comment reported by the Institute for the Study of War (ISW) in which Russian President Vladimir Putin suggested creating a “demilitarized” or “sanitary” zone in Ukraine that would put Russian territory and illegally occupied parts of Ukraine out of range of Ukrainian weapons. Putin included the city of Kharkiv within the proposed demilitarized zone. The notion of territorial concessi…