The floor leader of the ruling Grand National Party (GNP) Wednesday opposed using the Assembly speaker\'s authority to pass the long-pending free trade deal with the United States on the floor, saying a unilateral passage would cause distrust in party politics.Since the U.S. Congress endorsed the pact in early October during President Lee Myung-bak\'s state visit, Korea\'s rival parties have been deadlocked over the free trade deal with the U.S., with the opposition parties asking for a revision of an investor-state dispute (ISD) settlement provision.