In recent years, internet sales have grown by nearly 15 percent per year, compared to 4 percent per year for brick-and-mortar retail sales. Although e-commerce represents less than 9 percent of total retail sales, this shift in where we shop is eroding states’ sales tax base. Under the Supreme Court’s 1992 decision in Quill Corp. v. North Dakota, sellers without a physical presence in a state cannot be required to collect and remit that state’s sales tax. As a result, online sellers have an artificial competitive advantage over local brick-and-mortar sellers, who must collect sales tax from their customers. Congress needs to end this unfair tax advantage.