Minnesota Transfer Railway Co. v. City of St. Paul

I agree that the amendment of the gross earnings tax law is constitutional. I agree also that it was competent for the legislature so to amend the old law as to subject railroad companies to assessments for previously instituted improvement, not complete however and not assessed for at the time of the amendment. "If the other necessary conditions exist," special assessments "may be authorized after, as well as before, the expenditure is incurred." Warren v. Street Commrs.187 Mass. 290, 72 N.E. 1022; Hall v. Street Commrs. 177 Mass. 434,59 N.E. 68.

So it is not a question of power but of…