The notion that gain of territory is gain of wealth and strength for the state, after the expedient size has been won, is a delusion. In the Middle Ages the beneficial interest in land and the jurisdiction over the people who lived on it were united in one person. The modern great states, upon their formation, took to themselves the jurisdiction, and the beneficial interest turned into full property in land. The confusion of the two often reappears now, and it is one of the most fruitful causes of fallacy in public questions.
War with Canada isn’t much on people’s minds these days, but it was in 1896. Other hot topics of the day included possible annexation of Hawaii, the Cuba problem, and the pending split of Norway from Sweden. In those exciting times, Mr. Sumner wrote a great essay about the problems with territorial expansion (in particular) and what we today call “nation building”. Not all good thinking is recent, and this is well worth a read.