The broad lines of policy are ultimately laid down by the permanent interests of a country, although they may often be mistaken from short-sightedness or timidity, and although policy sometimes takes a course which does not seem warranted from the standpoint of lasting national benefits.

Policy is not an exact science, following necessary laws, but is made by men who impress on it the stamp of their strength or their weakness, and often divert it from the path of true national interests.

Such digressions must not be ignored.

The statesman who seizes his opportunity will often profit by these political fluctuations.

But the student who considers matters from the standpoint of history must keep his eyes mainly fixed on those interests which seem permanent.