...President Bush is beginning to promote the cause of tax reform. In his New York convention speech, Mr. Bush laid down the broad principles that tax reform must satisfy. With a friendly nod toward the desirability of home ownership (read the mortgage deduction) and charitable giving, he called for "a simpler, fairer, pro-growth system." And he's promised to appoint a bipartisan advisory panel to generate specific ideas.... Consider: Simplicity. The current system with its deductions, exemptions and credits -- many of which phase-in and then phase-out at different income levels -- piles complexity on complexity.... Fairness. Right now, the tax...