"...The Federal and State Governments are in fact but different agents and trustees of the people, instituted with different powers, and designated for different purposes."

"In America, the powers of sovereignty are divided between the government of the Union and those of the states. They are each sovereign with respect to the objects committed to it, and neither sovereign with respect to the objects committed to the other...."

"The two governments act in different manners and for different purposes...the general government in great national concerns, in which we are interested in common with other members of the Union; the state legislatures in our mere local concerns...They can no more clash than two parallel lines can meet." (The Creation of the American Republic at 529.)

"The necessity of a concurrent jurisdiction in certain cases results from the division of the sovereign power; and the rule that all authorities of which the States are not explicitly divested in favour of the Union remain with them in full vigor, is not only a theoretical consequence of that division, but is clearly admitted by the whole tenor of that instrument which contains the articles of the proposed constitution. We there find that notwithstanding the affirmative grants of general authorities, there has been the most pointed care in those cases where it was deemed improper that the like authorities should reside in the States, to insert negative clauses prohibiting the exercise of them by the States. The tenth section of the first article consists altogether of such provisions. This circumstance is a clear indication of the sense of the Convention, and furnishes a rule of interpretation out of the body of the act which justifies the position I have advanced, and refutes every hypothesis to the contrary."

"In Ableman v. Booth, 21 How. 523, Chief Justice Taney described in plain language the complex nature of our government, and the existence of two distinct and separate sovereignties within the same territorial space, each of them restricted in its powers, and each, within its sphere of action prescribed by the Constitution of the United States, independent of the other. Neither is under the necessity of applying to the other for permission to exercise its lawful powers. Within its own sphere, it may employ all the agencies for exerting them which are appropriate or necessary, and which are not forbidden by the law of its being..."