The general doctrine of the Osborn case has never been departed from, and it has sustained innumerable suits which have protected property rights from the enforcement of state statutes in conflict with the Constitution of the United States. It is no exaggeration to say that this doctrine, more than any other, has rendered the Constitution an effective shield against oppressive, tyrannical and confiscatory legislation, and compelled the states to obey the supreme law of the Constitution. The reasoning of Chief Justice Marshall is very logical and lucid, and it is most convincing. If, as was then conceded to be indisputable, the privilege or immunity of the state as principal was not communicated to the officer as agent, and if an action at law would lie against the officer in which full compensation ought to be made for a legal injury resulting from any unlawful act done in pursuance of an unconstitutional and void statute, there existed no reason why the preventive power of a court of equity should not equally apply to such an officer or why it should not restrain him from the commission of a wrong which it would punish him for committing. "If," continues the Chief Justice, "the party before the court would be responsible for the whole injury, why may he not be restrained from its commission, if no other party can be brought before the court?" It was pointed out that the very fact that the state could not be sued was a reason for permitting the suit to proceed in its absence against the officer or agent. We have here another example of how, in the evolution of legal principles, the same causes produce the same results. As in England the fact that the king could not be sued in the ordinary courts for a wrong led to the rule that his immunity or irresponsibility was not to be extended to his servants or agents and that the latter were to be held personally liable for whatever they did under the king's orders in violation of the legal rights of an individual, so with us the fact that a state could not be sued in a federal court led to the rule that its immunity or irresponsibility was not to be extended to its officers and that they were suable as responsible principals, even when acting under a state statute and as the agents or representatives of the state.