Ryan Ellis of ATR writes in to agree with me that they would not support a simple abolition of the mortgage deduction:

Taken as a standalone piece of legislation, we would absolutely oppose that, since it would be an annual tax increase of about $100 billion. As a stand-alone bill, this would in fact be a Taxpayer Protection Pledge violation.
However, we’re not opposed to a tax revenue-neutral shift. If you wanted to, for instance, you could eliminate this deduction and cut tax rates. Or, you could plow the money into other deductions or credits.
The main thing we want to avoid is a net income tax increase. That would be bad.

Indeed. There are ways to do it that could be politically acceptable — a flat tax might yet work — but for the moment it’s a distortion that this pesky democracy thing seems to have accepted. That doesn’t mean it’s right, however, or that we shouldn’t be trying to think of ways to make its removal acceptable to Murray, ATR, and Taylor (and I recognize that plowing the money into other deductions or credits wouldn’t pass the Taylor test and probably not the Murray test either . . . ).