NPR's Peter Kenyon reports on the tax cut debate today in the Senate. GOP leaders presented their 10-year, 792 billion dollar package, which President Clinton says he would veto. Other Republican senators and some Democrats, are offering an alternative set of tax cuts, totaling 500 billion dollars. But that package is also too big for the president. As the Senate was beginning debate, Federal Reserve Chairman Alan Greenspan testified in a Senate Budget Committee hearing, and warned against cutting taxes based on budget surpluses projected ten years out.