In a unanimous opinion authored by Justice Clarence Thomas, the US Supreme Court held today in Direct Marketing v. Brohl that the Tax Injunction Act does not bar out-of-state retailers from challenging a Colorado law requiring them to notify Colorado customers of the state’s sales and use tax requirement and to report tax-related information to those customers and the Colorado Department of Revenue.  The Court stated that the relief sought would not “enjoin, suspend or restrain the assessment, levy or collection” of Colorado’s sales and use taxes.  The Court left it to the US Court of Appeals for the Tenth Circuit to decide on remand whether the lawsuit might be barred under the comity doctrine which “counsels lower federal courts to resist engagement in certain cases falling within their jurisdiction.”