Joseph P. Bradley, Union Pacific Railway v. Ryan…
“ It cannot be denied that bills in equity to restranin the collection of taxes illegally imposed have frequently been sustained. But it is well settled that there ought to be some equitable ground for relief besides the mere illegality of the tax; for it must be presumed that the law furnishes a remedy for illegal taxation. It often happens, however, that the case is such that the person illegally taxed would suffer irremediable damage, or be subject to vexatious litigation, if he were compelled to resort to his legal remedy alone. ”
