The day after President Clinton unveiled his version of middle-class tax cuts, a rhetorical tug-of war began between the White House and congressional Republicans over whose plan was fairest to taxpayers -- and how far toward the GOP camp Clinton's plan must move to win Republican approval. Even as Clinton aides continued hashing out additional provisions, Republicans chided the president as a johnny-come-lately and said the "Contract With America" gave citizens more benefits. (Incoming House Majority leader Richard Armey of Texas even dubbed Clinton's package "Contract-lite.") The White House, anticipating the barbs, threw a briefing featuring Treasury Secretary Lloyd Bentsen and others who said the GOP plans would send 46 percent of new tax relief to families making more than $100,000 a year, compared to 13 percent under the Clinton plan. But on another GOP idea they've criticized as a giveaway to the wealthy -- a capital gains tax cut -- Administration officials acknowledged for the first time that they might give ground. TIME White House correspondent Michael Duffy says Clinton aides will be "slowly unveiling cuts in spending next week as a way to keep the political momentum going."