Late last month, both Overstock and Amazon filed petitions within a day of each other in the U.S. Supreme Court to block a ruling earlier this year by New York’s Court of Appeals which would force online retailers to collect state sales tax. At the time, Overstock said it might take the case all the way to the Supreme Court; Amazon, which backs the Marketplace Fairness Act, said that it preferred to pursue federal legislation. Both have put aside their differences over Overstock’s pricing war on books and are working in tandem to prevent New York and other states from imposing a so-called “Amazon tax.” Amazon retained former U.S. solicitor general Theodore B. Olson and Overstock selected David C. Frederick, former assistant to the solicitor general and counselor to the inspector general, to represent them. If selected by the court, the case could overturn a 1992 Supreme Court decision that states can only collect sales tax from retailers with a physical presence in the state.

Against that backdrop, American Booksellers Association CEO Oren Teicher weighed in yesterday with an open letter to Amazon founder and CEO Jeff Bezos, which is posted on the ABA Web site. “Dear Jeff,” wrote Teicher. “I am puzzled. On the one hand, it’s been widely reported in the media that Amazon has come around to supporting efforts to collect sales taxes equitably. On the other hand, Amazon continues to go to extraordinary lengths to fight every reasonable step forward in establishing a level playing field with regard to sales tax fairness. Which is it?”

Noting that “you can’t have it both ways,” Teicher takes the retail giant to task for the Supreme Court filing and for firing its affiliates in Missouri and calls for it to collect sales tax like Main Street retailers that obey the law and support their communities. “That’s what retailers do,” he wrote in closing.

No comment on the post from Amazon.