H.R. 6824 (Online Sales Simplicity and Small Business Relief Act of 2018) Has been referred to the House Judiciary Committee. This bill sets out to ban retroactive taxation of internet commerce with an imposition limitation on sales that occurred prior to June 21, 2018 (sec 2). The bill also imposes an orderly phase-in of compliance obligations for sales that occur after January 1, 2019 (sec 3).
See the bill as introduced September 13, 2018 below: