ost-offices and
post-roads; to issue copyrights and patents; to define and punish
felonies committed on the high seas, and offences against the law of
nations; to declare war, grant letters of marque and reprisal, and
make rules concerning captures on land and water; to raise and
support an army and navy, and to make rules for the regulation of
the land and naval forces; to provide for calling out the militia
to suppress insurrections and repel invasions, and to command this
militia while actually employed in the service of the United States.
The several states, however, train their own militia and appoint
the officers. Congress may also establish a uniform rule of
naturalization, and uniform laws on the subject of bankruptcies. It
also exercises exclusive control over the District of Columbia,[23]
as the seat of the national government, and over forts, magazines,
arsenals, dockyards, and other needful buildings, which it erects
within the several states upon land purchased for such purposes with
the consent of the state legislature.

[Footnote 23: Ceded to the United States by Maryland and Virginia.]

[Sidenote: The "Elastic Clause."]
Congress is also empowered "to make all laws which shall be necessary
and proper for carrying into execution the foregoing powers and all
other powers vested by this Constitution in the government of the
United States, or in any department or office thereof." This may be
called the Elastic Clause of the Constitution; it has undergone a
good deal of stretching for one purpose and another, and, as we shall
presently see, it was a profound disagreement in the interpretation of
this clause that after 1789 divided the American people into two great
political parties.

[Sidenote: Powers denied to the states.]
[Sidenote: Paper currency.]
The national authority of Congress is further sharply defined by the
express denial of sundry powers to the several states. These we have
already enumerated.[24] There was an especial reason for prohibiting
the states from issuing bills of credit, or making anything but gold
and silver coin a tender in payment of debts. During the years 1785
and 1786 a paper money craze ran through the country; most of the
states issued paper notes, and passed laws obliging their citizens to
receive them in payment of debts. Now a paper dollar is not money, it
is only the government's promise to pay a dollar. As long as you can
send it to the treasury and get a gold dolla