It is true that the powers of Europe may carry on maritime wars against the Union; but it is always easier and less dangerous to undertake a maritime than a continental war. Maritime warfare requires only one species of effort. A commercial people which consents to furnish its government with the necessary funds is sure to possess a fleet. And it is far easier to induce a nation to part with its money, almost unconsciously, than to reconcile it to sacrifices of men and personal efforts. Moreover, defeat by sea rarely compromises the existence or independence of the people which endures it.
As for continental wars, it is evident that the nations of Europe cannot threaten the American Union in this way. It would be very difficult to transport and maintain in America more than 25,000 soldiers, an army which may be considered to represent a nation of about 2,000,000 men. The most populous nation of Europe, contending in this way against the Union, is in the position of a nation of 2,000,000 inhabitants at war with one of 12,000,000. Add to this that America has all its resources within reach, while the European is 4,000 miles distant from his, and that the immensity of the American continent would of itself present an insurmountable obstacle to its conquest.