OLYMPIA — The Washington Association of Realtors has launched a $1 million campaign aimed at squashing a proposed tax increase on real-estate sales. "We are committed to doing whatever it takes to prevent any increase," said Steve Francks, the association's executive vice president. "I've never seen our members this mobilized." The group has started running TV, radio and newspaper ads warning that the tax increase would cost homeowners thousands of dollars in "hard-earned equity" when they go to sell. But in their fight, the Realtors face an unlikely foe: the typically anti-tax Building Industry Association of Washington (BIAW). The homebuilders...