."[59] This decision also overruled an intermediate case, Trupiano
_v._ United States,[60] whereby the practical effect of the Harris
decision had been circumscribed by a ruling that even where a valid
arrest is made, a search without a warrant is not permissible if the
circumstances make it feasible to procure a warrant in advance.

Search of Vehicles

The Fourth Amendment has been construed "* * *, as recognizing a
necessary difference between a search of a store, dwelling house, or
other structure in respect of which a proper official warrant readily
may be obtained, and a search of a ship, motor boat, wagon, or
automobile for contraband goods, where is it not practicable to secure a
warrant because the vehicle can be quickly moved out of the locality or
jurisdiction in which the warrant must be sought. * * * The measure of
legality of such a seizure is, therefore, that the seizing officer shall
have reasonable or probable cause for believing that the automobile
which he stops and seizes has contraband liquor therein which is being
illegally transported."[61] Where officers have reasonable grounds for
searching an automobile which they are following, a search of the
vehicle immediately after it has been driven into an open garage is
valid.[62] The existence of reasonable cause for searching an automobile
does not, however, warrant the search of an occupant thereof, although
the contraband sought is of a character which might be concealed on the
person.[63]

Use of Evidence

To remove the temptation to ignore constitutional restraints on search
and seizure, evidence obtained in violation thereof is made inadmissible
against an accused in federal courts.[64] This is contrary to the
practice prevailing in the majority of States and has been severely
criticized as a matter of principle.[65] The Court has intimated
recently that the federal exclusionary rule is not a command of the
Fourth Amendment, but merely a judicially created rule of evidence which
Congress could overrule. In Wolf _v._ Colorado,[66] it ruled that while
that amendment is binding on the States, it does not prevent State
courts from admitting evidence obtained by illegal search. With respect
to the federal rule, Justice Frankfurter said: "* * * though we have
interpreted the Fourth Amendment to forbid the admission of such
evidence, a different question would be presented if Congress, under its
legislative powers, were to pass a statute purporti