In considerable measure Congress has in its legislation kept within the limits of the power conceded to it by Monroe, but, when it has thought it wise, it has not hesitated to overstep them, and its constitutional right so to do has for years been conceded.27

In California v. Central Pacific R. R. Co.28 was involved the power of Congress to construct, or to authorize individuals to construct railroads across the States and Territories. This power the court held to be implied not only in the power given to Congress to regulate commerce, but in its authority to provide for postal accommodations and military exigencies.