Compensatory tax doctrine cannot exclude legislation from constitutional trade freedoms and remains subject to constitutional restrictions. The compensatory tax doctrine permits a discriminatory tax only if the State identifies the intrastate burden it seeks to compensate, the tax on interstate commerce roughly approximates but does not exceed that burden, and the interstate and intrastate taxable events are substantially equivalent. Indian constitutional structure under Part XIII contains express limitations on freedom of trade and does not allow judicially created exemptions; thus compensatory tax legislation remains subject to Part XIII scrutiny and is not insulated merely because revenues fund facilities or recompense taxpayers.