The United States Supreme Court has declined to hear arguments in the Quinn v Washington case. Deferring to the lower court ruling has national ramifications for the ability of states to tax outside their borders, and leaves Washington as the only taxing authority in the nation to define a capital gains tax as an "excise tax."

The chance of any individual case being taken up by the Supreme Court is small, so the case being taken was always a long shot. This leaves voters with the final say on the tax, with an initiative on the ballot this November which would repeal the tax. Another initiative would ban all future income taxes in Washington.