“The United States cannot purchase a grant of land in, or concession of right of way over, the territories of another nation, as could an individual or a private corporation.”

Intercourse.—­While as an act of sovereignty a nation may shut out from its borders any or all of the rest of mankind, intercourse is so natural and is usually so mutually profitable that such prohibition is almost unknown among civilized nations.  Intercourse is regulated in different nations in various ways.  Some limit or control it by a passport system; some by special supervision of strangers; some by a protective tariff; others by giving to one nation commercial privileges not given to another.

Among the general rules that govern intercourse are these:  Aliens are entitled to protection from violence for themselves and their property.  They are amenable to the laws of the country in which they are sojourning, except in certain oriental and other partly civilized countries.  Aliens may expatriate themselves and may become naturalized in the land of their adoption.  “The right of emigration is inalienable; only self-imposed or unfulfilled obligations can restrict it.” [Footnote:  Heffter, quoted, in Woolsey’s International Law.]

The principle that crime should be tried and punished where committed stands in the way of the trial of a culprit who has escaped to another country.  But for mutual protection most of the civilized nations have treaties for the extradition of criminals.  The United States have extradition treaties with over twenty countries. (See How Criminals Are Extradited, page 337.)

Ambassadors and Consuls.—­We have considered briefly the rights and duties of individual sojourners in foreign lands.  Let us now consider the modes and means of intercourse between the governments themselves.

Formerly when a nation wished to come to an understanding with another it sent a special messenger clothed with necessary authority to act; but for about two hundred years these representatives have, as a rule, taken up their residence at the capitals of the countries to which they are sent.

There are various grades of these ambassadors.  Ours in order of rank are ambassadors, envoys-extraordinary and ministers plenipotentiary, ministers resident, envoys, charges d’affaires, and, temporarily, secretaries of legation.

“Ambassadors [including all of the above] always and everywhere have had special immunities and often something of a sacred character ...  Neither public authority nor private persons can use any force, or do any violence to him, without offending against the law of nations.” [Footnote:  Except that if necessary for self-defense, passive resistance may be made.] This immunity extends to his house, furniture, and attendants.  Except in extreme cases, he is exempt from civil or criminal process.

These diplomatic agents are appointees of the executive.  Official communications with the president are made through the secretary of state.  “In all negotiations between nations, sovereign should always speak to sovereign and minister to minister.”