Trump's tax outline is a great start

Let's face it; the mortgage interest deduction is a terrible idea. Homeowners love it, of course, but there's no reason government should incentivize people through the tax code to borrow hundreds of thousands of dollars to buy houses they wouldn't otherwise buy.

Thirty-three million households took this deduction in 2014, but many of them would benefit if it were abolished in favor of a lower tax rate for everyone. Still, this carve-out is now in the price of most homes, and therefore people would object strongly and justifiably to its overnight abolition.

Which brings us to one of the virtues of President Trump's plan to reform the personal income tax code. It starts to do away with the mortgage deduction not by killing it in cold blood, as it were, but by letting it wither on the vine. Although it would remain in place, it would become unnecessary for most people in practice.

That's because Trump's plan nearly doubles the standard deduction. That comes to $24,000 for a married couple. In order to pay that amount in mortgage interest in a single year, you would have to be in the first year of a mortgage greater than $500,000. If your mortgage interest and charitable deductions don't combine for $24,000, then you don't have to bother itemizing, which will also make your taxes a lot easier to do.

Another benefit is that everyone can get the standard deduction, renters and homeowners alike. That makes the system fairer because while it doesn't penalize homeowners (and might actually benefit all but the wealthiest ones) it also extends the same benefit to millions more people who prefer renting to buying.