While it is true that an absolute blockade of any port might be practically impossible at the present day, while it is true that submarines and torpedo-boats might compel blockading ships to keep at such distance from ports that many loopholes of escape would be open to blockade runners, yet it may be pointed out that even a partial blockade, even a blockade that made it risky for vessels to try to break it, would have a very deleterious effect upon the prosperity of the country and of every man, woman, and child within it.  A blockade like this was that maintained during the greater part of the Civil War by the Northern States against the Southern States.  This blockade, while not perfect, while it was such as to permit many vessels to pass both ways, was nevertheless so effective that it made it impossible for the Southern States to be prosperous, or to have any reasonable hope of ever being prosperous.  And while it would be an exaggeration to state that the navy itself, unaided by the army, could have brought the South to terms; while it would be an exaggeration to state that all the land battles fought in the Civil War were unnecessary, that all the bloodshed and all the ruin of harvests and of homesteads were unnecessary, nevertheless it does seem that so long as the navy maintained the blockade which it did maintain, the people of the South would have been prevented from achieving enough prosperity to carry on an independent government; so that their revolt would have failed.  The South, not being able to raise the blockade by means of their navy, might have tried to do so by sending an army into the Northern States, to whip the Northerners on their own ground; but this would clearly have been impossible.

The sentences above are not written with the intention of minimizing the services rendered by the army in the Civil War, or of detracting from the glory of the gallant officers and men who composed it, or of subtracting one jot or tittle from a grateful appreciation of their hardships and bloodshed; neither do they dare to question the wisdom of the statesmen who directed that the war should be fought mainly by the army.  Their sole intention is to point out that, if a meagre naval force could produce so great an effect against a country mainly agricultural, a very powerful naval force, blockading effectively the principal ports of a manufacturing country, would have an effect so great that it can hardly be estimated.

It is plainly to be seen that the effect of a blockade against a purely commercial country by a modern navy would be incomparably greater now than it was fifty years ago, for two very important reasons.  One reason is that the progress of modern engineering has made navies very much more powerful than they were fifty years ago; and the other reason is that the same cause has made countries very much more vulnerable to blockade, because it has made so many millions of people dependent upon manufacturing industries and