WASHINGTON (Reuters) - The U.S. State Department said on Monday it hoped it will be possible to find a resolution to NATO ally Turkey’s decision to buy the S-400 air defense system from Russia, which led the United States to impose sanctions on Turkey. “This decision left us no alternative,” Christopher Ford, Assistant Secretary of State for International Security and Nonproliferation told reporters on a conference call. “We hope that the Turkish government will be willing to engage with us in trying to find a resolution to this.”