NJUDICIAL FUNCTIONS

The power of Congress to confer jurisdiction on the lower federal courts
is qualified by the rule that before Congress can vest jurisdiction in
the inferior courts, they must have the capacity to receive it. The
capacity of the lower judiciary to receive jurisdiction is defined in
the enumeration of cases and controversies in article III. Consequently
in vesting courts with jurisdiction, Congress cannot go beyond this
enumeration.[638] It follows from the rule that constitutional courts
can perform only judicial functions that Congress, in vesting courts
with jurisdiction, cannot impose upon them nonjudicial duties such as
administering pensions,[639] deciding issues subject to later executive
or legislative action,[640] rendering advisory opinions, or opinions
which are not final and conclusive upon the parties,[641] or taking
jurisdiction of matters from which any essential element of the judicial
power has been abstracted.[642] To be sure, Congress may clothe some
matters of an administrative nature with the mantle of a case or
controversy and thereby make it a matter of judicial cognizance, as it
has done with naturalization proceedings,[643] the administration of
certain laws relating to the expulsion of aliens,[644] the limited
administration of funds received from the Government of Mexico to
compensate American citizens for claims against that government,[645]
and, of course, the traditional administration of bankrupt enterprises
through the medium of a receiver.

Federal-State Court Relations

PROBLEMS RAISED BY CONCURRENCY

The American Federal System with its dual system of courts, exercising
concurrent jurisdiction in a number of classes of cases, presents
numerous possibilities of inter-court conflicts and interference.
Subject to Congressional enactments to the contrary, the State courts
have concurrent jurisdiction over all the classes of cases and
controversies enumerated in article III except suits between States,
those to which the United States is a party, those to which a foreign
state is a party, and cases of admiralty and maritime jurisdiction. Even
in admiralty cases the State courts, though unable to exercise any
portion of admiralty or maritime jurisdiction by delegation or
otherwise,[646] may have a concurrent jurisdiction when the same issues
assume the form of a case at common law.[647] In addition to conflicts
arising out of concurrent jurisdiction, relations betw