Can a search of a bag be conducted without a search warrant?

Normally searches of private property must be performed pursuant to a search warrant. Arkansas v. Sanders, 442 U.S. 753, 758, 99 S.Ct. 2586, 2590, 61 L.Ed.2d 235 (1979). Searches conducted without a warrant "are per se unreasonable under the Fourth Amendment subject only to a few specifically established and well-delineated exceptions." Katz v. United States, 389 U.S. 347, 357, 88 S.Ct. 507, 514, 19 L.Ed.2d 576 (1967). Each of these exceptions is carefully drawn and is to be strictly construed. The burden is on those seeking the exemption to show the need for it.

One might claim that the search of the bag was part of the search of the car and so was within the automobile exception. But this is erroneous. See Arkansas v. Sanders, 442 U.S. at 765 n.13, 99 S.Ct. at 2593 n.13 (applicability of warrant requirement to searches of containers does not depend on whether they are seized from automobiles). And, in any event, the burden still is on the government to show that such a container search would be within the automobile exception. Cf. Arkansas v. Sanders, 442 U.S. at 763, 99 S.Ct. at 2593.