This government is based on innumerable laws, but these laws would be of no avail unless they were carried out; and every nation in the world has found that employment of a great deal of force is necessary in order that they shall be carried out.  This force is mainly exercised by the police of the cities; but many instances have occurred in the history of every country where the authority of the police has had to be supported by the army of the national government.  There is no nation in the world, and there never has been one, in which the enforcement of the necessary laws for the protection of the lives, property, and trade of the people has not depended ultimately on the army; and the reason why the army could enforce the laws was simply the fact that the army had the power to inflict suffering and death.

As long as a maritime country carried on trade within its own borders exclusively, as long as it lived within itself, so long as its people did not go to countries oversea, a navy was not necessary.  But when a maritime country is not contented to live within its own borders, then a navy becomes essential to guard its people and their possessions on the highways of the sea; to enforce, not municipal or national law, as an army does, but international law.

Now the desire of the people of a country to extend their trade beyond the seas seems in some ways not always a conscious desire, not a deliberate intent, but to be an effort of self-protection, or largely an effort of expansion; for getting room or employment.  As the people of a country become civilized, labor-saving devices multiply; and where one man by means of a machine can do the work of a hundred, ninety-nine men may be thrown out of employment; out of a hundred men who till the soil, only one man may be selected and ninety-nine men have to seek other employment.  Where shall it be gotten?  Evidently it must be gotten in some employment which may be called “artificial,” such as working in a shop of some kind, or doing some manufacturing work.  But so long as a people live unto themselves only, each nation can practically make and use all the machinery needed within its borders, and still not employ all the idle hands; and when the population becomes dense, employment must be sought in making goods to sell beyond the sea.  The return comes back, sometimes in money, sometimes in the products of the soil and the mine and the manufactures of foreign lands.

In this way every nation becomes like a great business firm.  It exports (that is, sells,) certain things, and it imports (that is, buys,) certain things; and if it sells more than it buys it is making money; if it buys more than it sells it is spending money.  This is usually expressed by saying that the “balance of trade” is in its favor or against it.

In a country like the United States, or any other great nation, the amount of exporting and importing, of buying and selling almost every conceivable article under the sun, is carried on in the millions and millions of dollars; and so perfect has the organization for doing this business become in every great country, that the products of the most distant countries can be bought in almost every village; and any important event in any country produces a perceptible effect wherever the mail and telegraph go.