In the war between the United States and Mexico, the latter had no fortifications on her land frontiers, and, with the single exception of Vera Cruz, her harbors were entirely destitute of defensive works. The Americans, therefore, had no obstacles of this kind to overcome on three of their lines of operation; and, when Scott had reduced Vera Cruz, his line of march was open to the capital. Moreover, nearly every seaport on the Gulf and Pacific coast fell into our hands without a blow. Had the landing of Scott been properly opposed, and Vera Cruz been strongly fortified and well defended, it would have been taken only after a long and difficult siege. Moreover, had the invading army encountered strong and well-defended fortifications on the line of march to Mexico, the war would, necessarily, have been prolonged, and possibly with a different result.
The Russian fortifications in the Baltic prevented the allies from attempting any serious operations in that quarter, and those in the Black Sea confined the war to a single point of the Heracleidan Chersonese. Had Russia relied exclusively upon her fleet to prevent a maritime descent, and left Sebastopol entirely undefended by fortifications, how different had been the result of the Crimean war.
This subject will be alluded to again in the Notes on Sea-coast Defences, and Permanent Fortifications.
The war in Mexico exhibited, in a striking manner, our superiority over the enemy in this branch of the military art. No army was better supplied than ours in all matters of subsistence, clothing, medical and hospital stores, and in means of transportation. Two points, however, are worthy of remark in this connection: 1st. The great waste of material, which resulted from the employment of raw troops under short enlistments, and commanded by officers appointed from civil life, who were without experience and destitute of military instruction; and, 2d. The immense expense of transportation, which was due in part to the above cause and in part to the employment, in the administrative departments, of civilians who were utterly ignorant of the rules and routine of military service. This war was conducted on the system of magazines and provisions carried in the train of the army, or purchased of the inhabitants and regularly paid for, forced requisitions being seldom resorted to, and then in very moderate quantities. The wisdom of this plan was proved by the general good order and discipline of our troops, and the general good-will of the non-combatant inhabitants of the country which was passed over or occupied by the army.