If Trump runs against Hillary, there is a significant percentage of Berners who will vote Trump for the reasons you list. They’ll never admit it publicly (because of leftist mania), but it’s there.
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Case in point - the Libya intervention - the GOPe establishment only concentrated on the Benghazi fiasco - but the GOPe fully supported the overthrow of Gaddafi just like Hillary did. Trump and Bernie both come out against the overthrow and against missions of war like that and the establishment of Dems and Repubs freak out.