Eric Boehm explains why an obscure US Supreme Court ruling is making life extremely complicated for thousands and thousands of online businesses:

… Until last year, that meant Heitman was responsible for collecting and paying sales taxes to exactly one place: the Wisconsin Department of Revenue. But thanks to an under-the-radar ruling from the U.S. Supreme Court in June, he’s now receiving letters, phone calls, and emails from revenue officials across the country, each wanting a piece of his business.

The source of Heitman’s frustrations is Wayfair v. South Dakota, which allowed states to collect sales taxes from online businesses located beyond their borders. Many states view the Wayfair ruling as a potential tax revenue windfall in which the taxes are paid by non-residents who can’t vote against them. That’s why businesses like Heitman’s are now facing the chilling prospect of owing taxes in dozens, and possibly hundreds, of different jurisdictions — while being hounded by out-of-state tax collectors.

Since the Supreme Court issued its ruling in June, Heitman has been scrambling to become compliant with tax commissions and revenue departments from coast to coast. He’s spent thousands of dollars on new software to help navigate the complexities of state sales tax law, but that’s only been so much help. “It almost seems like I have another full time job dumped on me with this sales tax thing,” he says. “It’s burning me out.”

As the 2019 tax season begins, states are ramping up efforts to squeeze extra revenue out of remote retailers like Heitman, putting an expensive new burden on businesses that have found broad customer bases online. The burden is particularly large in the five U.S. states that charge no sales tax, where entrepreneurs could now be charged with paying a tax they have never had to pay before, to a government over which they have no voice. And while Congress could clean up the Supreme Court’s mess, it’s far from certain that it will.

Warren Meyer points out that it’s not just the individual states who are taking advantage of this windfall opportunity to collect taxes from non-residents:

Like most writers, Mr. Boehm actually understates the problem. Because the potential exists not to have 50 new taxing authorities for every sales, but thousands. I have to deal with this every day. I wrote a while back:

Take Arizona, which seems from my experience to be roughly average. The sales tax rate table is 18 pages long in a small font. There are 29 separate rate categories which each have different rates in each of Arizona’s 15 counties. My business is in 6 counties and we have 3 rate categories that apply, or 4 if you consider items with no tax as another rate category. This is 24 different state/county sales tax rates we charge. But that is the easy part. Because then there are, in addition to county taxes, 92 different towns and cities that have their own rate tables with up to 29 different rate categories that add to the base state/county rate. Other states such as Washington (rule of thumb — if the state has no income tax then it has a LABYRINTHIAN sales and business tax systems) have additional overlay taxes such as for transit and stadium districts.

When my company opens a new location, we have to spend hours on the Internet and with maps trying to figure out what sales taxes to collect, and even with good due diligence we sometimes get it wrong and find in an audit we are actually just inside or outside some line where the rate changes (we once had a location 30 miles outside of Seattle on a long dirt road where we found we had to collect the Seattle Rapid Transit tax). Thatcher, AZ is a town of like 4000 people but has its own special sales tax rates — do you know where the town line is? Well neither do they, because last time I checked they did not have any sort of online lookup system to tell one automatically if the address is inside or outside the town and its sales tax district…

But even after registering in all 50 states, you are STILL not done, because many states don’t have a fully unified sales tax collection system. In Arizona, for example, the larger cities require their own registration and monthly reporting.

Meyer is operating a company that has physical assets and employees in each of the states and lesser jurisdictions to which taxes are due. Internet businesses generally only have physical assets in a single state, yet an expansive reading of the Wayfair ruling (the type of reading most jurisdictions will prefer) makes them liable for taxes almost everywhere.