The United States must \"stand up and act\" to punish the Syrian regime and cannot resort to isolationism in the face of \"slaughter,\" Secretary of State John Kerry told lawmakers Tuesday. \"This is not the time for armchair isolationism. This is not the time to be spectators to a slaughter,\" Kerry told the Senate Foreign Relations Committee. \"We have spoken up against unspeakable horror. Now we must stand up and act,\" he said, according to prepared remarks.