FILE PHOTO – Crates filled with 2011 tax forms are seen at the 96th Street Public Library in New York April 17, 2012. (Photo: Reuters)
The federal income tax is corrosive and destructive. It’s almost as if a group of malicious people decided to deliberately design a system that imposes maximum damage while also allowing the most corruption.
The economic damage is not only the result of high tax rates and pervasive double taxation, but also because of loopholes that exist to bribe people into making economically unwise decisions.
These include itemized deductions for mortgages and charitable contributions, as well as the fringe benefits exclusion and the exemption for municipal bond interest. And there are many other corrupt favors sprinkled through a metastasizing tax code.
But there’s a strong case to be made that the worst loophole is the deduction for state and local taxes. Why? For the simple reason that it encourages, enables, and subsidizes bad policy.
Here’s how it works. State and local lawmakers can increase income taxes or property taxes and be partially insulated from political blowback 
because their taxpayers can deduct those taxes on their federal return.
And it’s a back-door way of giving a special break to upper-income taxpayers because the deduction is more valuable to people in higher tax brackets.
Let’s look at an example that’s currently in the news. Democrats in the Illinois state legislature want a big increase in the personal income tax. If they succeed and boost taxes by an average of $1000, high-income taxpayers who take advantage of the deduction may only suffer a loss of as little as $600 since their federal tax bill may fall by almost $400.
For politicians, this is an ideal racket. They can promise various interest groups $1000 of goodies while reducing take-home pay by a lesser amount.
Let’s review some recent commentary on this topic.
The Wall Street Journal opined on the issue last weekend.
Chuck Schumer aspires to raise taxes on every rich person in America, save one protected class: coastal progressives. …Like many other Democrats, he’s apoplectic about a plan to end the state and local tax deduction. …One goal of tax reform is to reduce unproductive tax loopholes, and ending the state and local deduction would generate revenue to finance lower rates: The deduction is worth about $100 billion a year… About 88% of the benefits in 2014 flowed to taxpayers who earn more than $100,000, while 1% went to those who earn less than $50,000. California alone reaps nearly 20% of the benefit…and a mere six states get more than half. …The folks underwriting this windfall are in Alaska, South Dakota, Wyoming and other places without a state income tax. …Eliminating the deduction would be a powerful incentive for Governors to cut state taxes on residents who are suddenly exposed to their full liability. …killing the state and local deduction would pay a double dividend: The first is creating a more equitable tax code with a broader base and lower rates. The second is spurring reform in states that are long overdue for a better tax climate.
Writing earlier this year for National Review, Kevin Williamson was characteristically blunt.
It’s time for…blue-state…tax increases that would fall most heavily on upper-income Americans in high-tax progressive states such as California and New York. …eliminate the deduction for state income taxes, a provision that takes some of the sting out of living in a high-tax jurisdiction such as New York City (which has both state and local income taxes) or California, home to the nation’s highest state-tax burden. Do not hold your breath waiting for the inequality warriors to congratulate Republicans for proposing these significant tax increases on the rich. …allowing for the deduction of state taxes against federal tax liabilities creates a subsidy and an incentive for higher state taxes. California in essence is able to capture money that would be federal revenue and use it for its own ends, an option that is not practically available to low-tax (and no-income-tax) states such as Nevada and Florida. It makes sense to allow the states to compete on taxes and services, but the federal tax code biases that competition in favor of high-tax jurisdictions.
And Bob McManus adds his two cents in an article for the Manhattan Institute’s City Journal.
Voters in all heavy-tax, high-spending states have no one to blame for their situation save themselves. At a minimum, it seems clear that deductibility—by softening the impact of federal taxation—encourages outsize state and local spending. States that take advantage of deductibility—mostly in the Northeast and on the West Coast—are in effect subsidized by states that have kept tighter control on their spending. …New York’s top-of-the-charts spending puts the state at the pinnacle…with New Yorkers paying a national high of 12.7 percent of income in state and local levies. Local property taxes in New York are astronomical and not coming down any time soon. …deductibility has powerful friends—among them the public-employee unions… New York and the nation would benefit if deductibility was jettisoned. …end the incentive for the tax-and-spend practices that have been so economically corrosive to big-spending Blue states.
Let’s close with the should-be-obvious point that the goal isn’t to repeal the state and local tax deduction in order to give politicians in Washington more money to spend. Instead, every penny of that revenue should be used to finance pro-growth tax reforms.
That creates a win-win situation of better tax policy in Washington, while also creating pressure for better tax policy at the state and local level.
For what it’s worth, both Trump and House Republicans are proposing to get rid of the deduction.
