Four blue states filed a lawsuit yesterday, claiming that the Tax Cuts and Jobs Act’s limitation on the state and local tax (SALT) deduction is unconstitutional. If I were a taxpayer in one of those states (I am, actually) this lawsuit wouldn’t exactly encourage me to put away my checkbook.

The states--New York, New Jersey, Connecticut, and Maryland—argued that the new law “eviscerates” the SALT deduction, which has been part of every federal income tax since 1862. The SALT cap, the states argue, “interferes with the states’ sovereign authority” to make their own tax and spending choices.

I am no legal scholar, so I asked both a tax and a constitutional lawyer what they thought. Both felt the states’ legal case was a reach. It is true that the SALT deduction has been around since the dawn of the federal income tax. And there is little doubt that many of the lawmakers who supported the TCJA explicitly wanted to limit the ability of state and local governments to raise taxes and spend money. But that doesn’t mean the US Constitution prohibits the curbs.

Besides, there is nothing new about Congress imposing limits on the SALT deduction. For example:

• When Congress adopted the standard deduction in 1944, it severely limited the scope of the SALT deduction for many taxpayers.
• Until the mid-1980s, nearly all state and local taxes were deductible on federal returns. But the Tax Reform Act of 1986 barred taxpayers from deducting state sales taxes from federal taxable income. Then, in 2004, Congress changed the rules again. This time it gave taxpayers a choice to deduct either sales tax or income tax but not both.
• In 1990, Congress reduced most itemized deductions, including the SALT deduction, for some high-income taxpayers through a law known as the Pease provision (named for the congressman who introduced it). Then Congress repealed Pease in last year’s TCJA.
• Most importantly, until it was largely repealed in the TCJA, the old individual Alternative Minimum Tax also effectively limited the ability of many taxpayers to fully deduct their state and local taxes.

The point, of course, is that while the SALT deduction has been around since the Civil War, Congress has revised it many times and in many ways. It is hard to see how the TCJA’s SALT limits are anything more than just another alteration. Besides, most taxpayers affected by the cap on their SALT deductions still got a net tax cut from the 2017 law. And many states received a tax windfall.

The lawsuit will proceed through the legal system. But it seems unlikely to affect taxpayers anytime soon. The IRS has promised guidance shortly on both the SALT deduction and on various state work-arounds. Among the plaintiffs, New York, New Jersey, and Connecticut have already enacted relief for their residents who are facing the SALT deduction cap.

While the states and feds duke it out in the courts, the IRS is likely to enforce the SALT deduction cap. And, who knows, since the individual income tax changes in the TCJA are only temporary, the cap may expire before all the litigation is resolved.

States may or may not have a legitimate complaint against the latest limits on the SALT deduction. But the place for them to resolve it is Congress, not the courts.