Arizona Gov. Evan Mecham should go back to selling cars, former Sen. Barry Goldwater said as he became honorary chairman of former Rep. John Rhodes' campaign to oppose the embattled governor in a recall election. Goldwater, who backed Mecham during the 1986 campaign, said at a news conference in Phoenix that his endorsement of the auto dealer was a mistake. Meanwhile, Atty. Gen. Bob Corbin issued an opinion that could open the door to a movement to draft acting Gov. Rose Mofford, a Democrat, into the May 17 recall election. Corbin's non-binding opinion said an officeholder who is drafted would not be required to quit his or her current post, as required by Arizona's "resign to run" law.