WASHINGTON -- As House and Senate tax writers head into talks over $70 billion in tax cuts, new estimates show that the alternative minimum tax could hit 23 million individuals and families next year. Sen. John Kerry, D-Mass., asked the Joint Committee on Taxation to estimate the growth in a tax that increasingly threatens middle-income taxpayers. It originally was intended to prevent wealthy individuals from avoiding taxation. Lawmakers in recent years have enacted temporary fixes to blunt the tax's impact. Without such a fix, the committee's staff of tax experts who advise lawmakers estimated 23 million taxpayers could feel the...