European Union diplomacy to resolve a dispute with Turkey in the Mediterranean has become bogged down in competing initiatives a week before a summit meant to show Ankara a united front, according to EU member state envoys. The impasse, which EU envoys were unable to break at a meeting on Wednesday, is holding up unrelated sanctions against Belarus and underscores the paralysis in foreign policy that the EU’s chief executive berated publicly in a speech on Wednesday. “It’s an extremely difficult issue,” one senior member state diplomat said.