In a tax code with no shortage of ironies, the alternative minimum tax (AMT) stands out. Created by Congress in 1969, it was aimed at millionaires, but relatively few millionaires pay it. It is billed as a low-rate levy, but most of its victims face higher taxes because of it. It undermines two widely lauded reforms of the income tax -- restoring both bracket creep and the marriage penalty. And though nobody favors keeping this Frankenstein alive, it will be very difficult to kill. Welcome to the tax policy twilight zone.