A Big, Bold, Backward Tax Idea

(The Bloomberg View) -- The Treasury Department is apparently looking into using its regulatory power to change the way taxes on capital gains are assessed. The idea is to confine the taxes to real, inflation-adjusted gains, not nominal gains, as now. There's a particle of sense in this notion, but it's buried miles deep in bad faith and bad economics.

The change would amount to a tax cut that the country cannot afford. Its benefits — even by the standard of recent Republican thinking on tax reform — would be heavily skewed toward the very wealthy. The change would open vast new opportunities for tax avoidance. And this far-reaching alteration to the tax code would be done without involving Congress.

Unaffordable, unfair, inefficient and quite possibly unlawful — for just one idea, that's impressive.

According to the Tax Policy Center, using the most recent data, about one-third of capital gains could be attributed to inflation in 2012. Full indexing would have cut taxes on those gains by about $30 billion. Allowing for various offsets, the net revenue loss if the plan were implemented would be $10 billion to $20 billion a year — enough to make a serious fiscal problem worse.

The federal government is already borrowing close to a trillion dollars a year, partly thanks to the recent tax-reform law, and that's with the economy at or close to full employment. Government debt held by the public stands at almost 80 percent of gross domestic product and is on track to rise to 150 percent of GDP over the next 30 years. To pile another tax cut on top of this would be madness.

The earlier reform failed as well on fiscal fairness and efficient tax collection — but nothing like this new idea does. Cutting capital-gains taxes without making other changes is about the most regressive thing that could be done to the tax code. And indexing capital gains for inflation without indexing capital expenses (such as interest payments and depreciation) would create an array of new tax shelters.

What about the particle of good sense? In a comprehensive plan, you could deal with the revenue shortfall by raising rates and closing loopholes. And you could advance fairness by making the code more progressive in other ways. Then, comprehensive (not partial) indexation would make the tax code more neutral. At present, the taxes that people and firms expect to pay depend on future inflation, which creates uncertainty and other distortions. Other things equal, it would be better to have a code that was inflation-proof.

Other things aren't equal, however. As it stands, the plan is a terrible idea that should be dropped immediately. If not, there's hope it will succumb in short order to the legal challenges it will surely provoke.

Editorials are written by the Bloomberg View editorial board.