Article I, Section 8, Clause 7:

[The Congress shall have Power . . . ] To establish Post Offices and post Roads; . . .

In determining the extent to which state laws may impinge upon persons or corporations whose services are used by Congress in executing its postal powers, the task of the Supreme Court has been to determine whether particular measures are consistent with the general policies indicated by Congress. Broadly speaking, the Court has approved regulations having a trivial or remote relation to the operation of the postal service, while disallowing those constituting a serious impediment to it. Thus, the Court held a state statute granting one company an exclusive right to operate a telegraph business in the state to be incompatible with a federal law that granted any telegraph company the right to construct its lines upon post roads.1 The Court interpreted the federal statute to prohibit state monopolies in a field Congress was entitled to regulate in exercising its combined power over commerce and post roads.2

The Court also held an Illinois statute that, as construed by the state courts, required an interstate mail train to make a detour of seven miles in order to stop at a designated station to be an unconstitutional interference with Congress’s postal power.3 However, the Court held that a Minnesota statute requiring any intrastate train to stop at county seats “directly on its course, for a few minutes,” was “a reasonable exercise of police power” and not “an unconstitutional interference with . . . the transportation of the mails of the United States.” 4

Local laws classifying postal workers with railroad employees for the purpose of determining a railroad’s liability for personal injuries,5 or subjecting a union of railway mail clerks to a general law forbidding any “labor organization” to deny any person membership because of his race, color or creed,6 have been held not to conflict with national legislation or policy in this field. A state also may arrest a postal employee charged with murder while he is engaged in carrying out his official duties,7 despite the interference pro tanto with the performance of a federal function, but it cannot punish a person for operating a mail truck over its highways without a valid state driver’s license.8

Footnotes

1

Pensacola Tel. Co. v. Western Union Tel. Co., 96 U.S. 1 (1878).

2

Id. at 11.

3

Illinois Cent. R.R. v. Illinois, 163 U.S. 142 (1896) (characterizing it as “a statute . . . which unnecessarily interferes with the speedy and uninterrupted carriage of the mails of the United States,” and contrasting it with “a reasonable police regulation of the State” ). Id. at 154.

4

Gladson v. Minnesota, 166 U.S. 427 (1897).

5

Price v. Pennsylvania R.R., 113 U.S. 218 (1895); Martin v. Pittsburgh & Lake Erie R.R., 203 U.S. 284 (1906).

6

Railway Mail Ass’n v. Corsi, 326 U.S. 88 (1945).

7

United States v. Kirby, 74 U.S. (7 Wall.) 482 (1869) ( “the act of Congress which punishes the obstruction or retarding of the passage of the mail, or of its carrier, does not apply to a case of temporary detention of the mail caused by the arrest of the carrier upon an indictment for murder.” ). Id. at 484.

8

Johnson v. Maryland, 254 U.S. 51, 57 (1920) ( “the immunity of the instruments of the United States from state control in the performance of their duties extends to a requirement that they desist from performance until they satisfy a state officer upon examination that they are competent for a necessary part of them and pay a fee for permission to go on.” ).