“Because that’s where the money is.”
–bank robber Willie Sutton, explaining why he targeted banks
For the same reason Willie Sutton robbed banks, financially strapped governments (federal and state) inevitably are going to revisit the home mortgage interest deduction as they seek to close record deficits. (Also getting scrutiny: deductions for state property taxes.)
According to some estimates, doing away with the mortgage interest deduction completely could raise as much as $100 billion in additional revenue annually (read, taxes).
As policymakers try to restrain themselves, though, they should ask: what will that do to housing prices?
Given that the cumulative value of all U.S. housing is something like $16.5 trillion, according to Freddie Mac, even a 1% drop would destroy $165 billion in value, swamping the “benefit” of increased tax revenues.
Even that arguably understates the damage, due to a phenomenon called the “wealth effect” — basically, economic-speak for people consuming more (or less) as their wealth fluctuates.
So, the ultimate economic hit would likely be a multiple of the $165 billion drop in home prices.
In view of the foregoing, what’s far more likely is some combination of a cap on deductions, means testing, and the like.
P.S.: our legal system has a principle, called stare decisis, that requires judges to defer to — rather than disturb — established precedent. Literally tens of millions of Americans going back decades have bought homes with the expectation that the mortgage interest deduction would be respected.
If that isn’t long-established precedent — I don’t know what is!