The power to determine the relations between this government and other governments extends also to the determination of the rights and privileges which shall be accorded to the subjects of foreign governments, either in relation to property within the jurisdiction of this government, or the personal privileges which shall be accorded to them within the limits of the United States. As will appear in the next section, these rights and privileges may be determined by treaty. But in the absence of treaty provisions, the presence of aliens within the limits of the United States is within the control of the executive department. Congress, in the exercise of the legislative power, may provide for the exclusion of aliens, or the deportation of aliens who have been permitted to come within the limits of the United States but have not acquired or are not permitted to acquire the rights of citizenship. The enforcement of the regulations made by Congress rests with the executive, primarily, and not with the courts.

While the policy of the federal government has in general been to permit aliens freely to come into this country, and reside here, enjoying the same personal and property rights as citizens, this policy has been within recent years modified in two important respects: (1) by excluding immigrants who belong to the criminal classes or are likely to become charges on the public, or are afflicted with contagious diseases so that their admission would imperil the general health, or who are brought in under contract binding them to service; (2) by excluding the Chinese, whose presence in large numbers was thought to be inimical to the general public welfare.

The restrictions on immigration might be supported under the power of Congress to regulate commerce with foreign nations (see above, § 93), but the total exclusion of the Chinese, and provisions for the deportation of persons of that nationality who refuse to comply with certain regulations as to their residence in this country, rest on a higher power than that involved in the regulation of commerce, and can be supported only on the theory that the federal government may control not only the relations of this government with foreign governments, but also the relations of this government with the subjects of foreign governments (Chinese Exclusion Case; and see United States v. Williams as to deportation of anarchists).