Letting homeowners deduct interest paid on their mortgages from taxable income makes no sense. It encourages taking on more debt, discriminates against renters, subsidizes one kind of spending over others and favors the upper incomes. It advances the questionable public goal of making more Americans into homeowners. And it costs the Treasury about $100 billion a year.

Although the mortgage-interest deduction is bad policy on numerous fronts, neither party seems keen to take it on. The real-estate industry portrays any cross-eyed look at the loophole as a frontal assault on the American Dream.

To their credit, Republicans baby-stepped in the right direction by trying to drop their usual support for the mortgage-interest deduction from their party platform. Candidate Mitt Romney has called for revenue-neutral tax reform that would lower federal income-tax rates while getting rid of loopholes – what is called “broadening the tax base.” (He refuses to be specific on which ones he’d close.) By leaving out mention of the mortgage deduction, the platform would push the message along.