in their jurisdiction. It was established, on the one hand, that certain parties must always be brought before the Federal courts, without any regard to the special nature of the cause; and, on the other, that certain causes must always be brought before the same courts, without any regard to the quality of the parties in the suit. These distinctions were therefore admitted to be the bases of the Federal jurisdiction.
Ambassadors are the representatives of nations in a state of amity with the Union, and whatever concerns these personages concerns in some degree the whole Union. When an ambassador is a party in a suit, that suit affects the welfare of the nation, and a Federal tribunal is naturally called upon to decide it.
The Union itself may be involved in legal proceedings, and in this case it would be alike contrary to the customs of all nations, and to common sense, to appeal to a tribunal representing any other sovereignty than its own; the Federal courts, therefore, take cognizance of these affairs.
When two parties belonging to two different States are engaged in a suit, the case cannot with propriety be brought before a court of either State. The surest expedient is to select a tribunal like that of the Union, which can excite the suspicions of neither party, and which offers the most natural as well as the most certain remedy.
When the two parties are not private individuals,