The simplest and most natural method of providing for the exercise of federal jurisdiction as to classes of cases which are by the constitution declared to be within the scope of the federal judicial power is by providing courts in which such suits may be originally brought; and there are courts provided, as described in the next chapter, in which controversies arising under the constitution, laws, or treaties of the United States, and cases of admiralty and maritime jurisdiction, and suits by the United States, and suits by a state against another state, or against the citizens of another state, and suits by a citizen of one state against a citizen of another state, and by a citizen against an alien, or an alien against a citizen, may be originally instituted. The facts which make the case a proper one for the jurisdiction of the court in which it is brought must be stated, and the particular court in which the suit is instituted will not have jurisdiction, unless, as already explained, the case is one within the enumeration of federal judicial power, and also one which may be tried in the court as constituted.