r The
War Brides Act of 1945,[1075] was held to be not reviewable by the
courts; nor were regulations on which the order was based invalid as
representing an undue delegation of legislative power. Said the Court:
"Normally Congress supplies the conditions of the privilege of entry
into the United States. But because the power of exclusion of aliens is
also inherent in the executive department of the sovereign, Congress may
in broad terms authorize the executive to exercise the power, e.g., as
was done here, for the best interests of the country during a time of
national emergency. Executive officers may be entrusted with the duty of
specifying the procedures for carrying out the congressional
intent."[1076]

In cases decided in March and April, 1952, comparable results were
reached: The Internal Security Act of 1950, section 23, in authorizing
the Attorney General to hold in custody, without bail, aliens who are
members of the Communist Party of the United States, pending
determination as to their deportability, is not unconstitutional.[1077]
Nor was it unconstitutional to deport under the Alien Registration Act
of 1940[1078] a legally resident alien because of membership in the
Communist Party, although such membership ended before the enactment of
the Act. Such application of the Act did not make it _ex post facto_,
being but an exercise of the power of the United States to terminate its
hospitality _ad libitum_.[1079] And a statutory provision[1080] which
makes it a felony for an alien against whom a specified order of
deportation is outstanding "to willfully fail or refuse to make timely
application for travel or other documents necessary to his departure" is
not on its face void for "vagueness."[1081]

The power of Congress to legislate with respect to the conduct of alien
residents is, however, a concomitant of its power to prescribe the terms
and conditions on which they may enter the United States; to establish
regulations for sending out of the country such aliens as have entered
in violation of law; and to commit the enforcement of such conditions
and regulations to executive officers. It is not a power to lay down a
special code of conduct for alien residents or to govern private
relations with them. Purporting to enforce the above distinction, the
Court, in 1909, held void a statutory provision which, in prohibiting
the importation of "any alien woman or girl for the purpose of
prostitution," provided furt