The “Amazon tax” is just the latest in a series of efforts to eliminate the long-standing “physical presence” standard and replace it with a nebulous, arbitrary standard of “economic presence.” Businesses throughout our nation’s history could always ply their trade across state lines. Today, with new technologies, even the smallest businesses can more easily reach across geographical borders to sell their products and services in all fifty states. If such sales can now expose these businesses to tax compliance and liability risks in states where they merely have customers, they will be less likely to expand their reach into those states.