The radical disadvantage of the defensive is evident. It not only is the enforced attitude of a weaker party, but it labors under the further onerous uncertainty where the offensive may strike, when there is more than one line of operation open to him, as there usually is. This tends to entail dissemination of force. The advantages of the defensive have been sufficiently indicated; they are essentially those of deliberate preparation, shown in precautions of various kinds. In assuming the defensive you take for granted the impossibility of your own permanent advance and the ability of the enemy to present himself before your front in superior numbers; unless you can harass him on the way and cause loss enough to diminish the inequality. Unless such disparity exists, you should be on the offensive. On the other hand, in the defensive it has to be taken for granted that you have on your side a respectable though inferior battle fleet, and a sea frontier possessing a certain number of ports which cannot be reduced without regular operations, in which the armed shipping can be got ready for battle, and to which, as to a base, they can retire for refit. Without these two elements there can be no serious defense. 10. COMMERCE-DESTROYING AND BLOCKADE[29] It is desirable to explain here what was, and is, the particular specific utility of operations directed toward the destruction of an enemy’s commerce; what its bearing upon the issues of war; and how, also, it affects the relative interests of antagonists, unequally paired in the matter of sea power. Without attempting to determine precisely the relative importance of internal and external commerce, which varies with each country, and admitting that the length of transportation entails a distinct element of increased cost upon the articles transported, it is nevertheless safe to say that, to nations having free access to the sea, the export and import trade is a very large factor in national prosperity and comfort. At the very least, it increases by so much the aggregate of commercial transactions, while the ease and copiousness of water carriage go far to compensate for the increase of distance. Furthermore, the public revenue of maritime states is largely derived from duties on imports. Hence arises, therefore, a large source of wealth, of money; and money—ready money or substantial credit—is proverbially the sinews of war, as the War of 1812 was amply to demonstrate. Inconvertible assets, as business men know, are a very inefficacious form of wealth in tight times; and war is always a tight time for a country, a time in which its positive wealth, in the shape of every kind of produce, is of little use, unless by freedom of exchange it can be converted into cash for governmental expenses. To this sea commerce greatly contributes, and the extreme embarrassment under which the United States as a nation labored in 1814 was mainly due to commercial exclusion from the sea.