Amazon is located in Washington, as a convenience to the user and to the state Amazon collects tax in accordance with Washington state law if someone ("user A")

Amazon is located in Washington, as a convenience to the user and to the state Amazon collects tax in accordance with Washington state law if someone ("user A") purchases an item from its site in Washington. This way "user A" in Washington doesn't owe the state any taxes for that purchase, and doesn't have to declare it on any tax forms. Now someone in California ("user B") purchases an item from Amazon. Amazon is located in Washington and in accordance with federal law is only required to collect taxes for the state it is located in. So "user B" buys the product and Amazon does NOT collect the California state tax. "user B" now has to put all of his purchases down on his tax forms, and pay the tax for the items he bought. Amazon had an affiliate program in California. This affiliate program was claimed by the state of California to mean that Amazon was located in California ("to constitute a physical presence"). If that is the case, then Amazon would legally be required to collect tax for "user B"'s purchase and remit it to the state of California. This would effectively mean that Amazon would now have to file taxes in Washington as well as California. Not a problem for a big corporation you say, imagine then that all 50 states implement said system, Amazon would now be on the hook for filing and paying tax in 50 different states, even-though it technically does not have a physical presence in the state. -- Local retailers have a physical presence in the state, and are by law required to be registered businesses and thus are required to collect state sales tax for the state they are in. If however they also shipped out to other states (lets say they are located in CA, and ship to NJ) they would not have to collect sales tax on the sale when shipping to NJ since that is interstate commerce. -- This may not seem fair, but if any company doing any business with another business or individual out of the state where they have a presence has to keep track and file tax paperwork for each state they do business with it would become unmanageable, especially for smaller businesses where doing tax for one single state is already a big burden, imagine having to do it for all 50 and each one having different laws or different rules regarding taxation. The states are basically attempting to close a loophole consumers are using, whereby they purchase items out of state so that they don't have to pay taxes on it, and then technically they are breaking the law by never declaring those items.