It is clear that we must either adopt our own tariff or that of Mexico, or establish a new system of duties.  Our own tariff could not be adopted, because the Mexican exports and imports are so different from our own that different rates of duties are indispensable in order to collect the largest revenue.  Thus upon many articles produced in great abundance here duties must be imposed at the lowest rate in order to collect any revenue, whereas many of the same articles are not produced in Mexico, or to a very inconsiderable extent, and would therefore bear there a much higher duty for revenue.  A great change is also rendered necessary by the proposed exaction of duties on all imports to any Mexican port in our possession from any other Mexican port occupied by us in the same manner.  This measure would largely increase the revenue which we might collect.  It is recommended, however, for reasons of obvious safety, that this Mexican coastwise trade should be confined to our own vessels, as well as the interior trade above any port of entry in our possession, but that in all other respects the ports of Mexico held by us should be freely opened at the rate of duties herein recommended to the vessels and commerce of all the world.  The ad valorem system of duties adopted by us, although by far the most just and equitable, yet requires an appraisement to ascertain the actual value of every article.  This demands great mercantile skill, knowledge, and experience, and therefore, for the want of skillful appraisers (a class of officers wholly unknown in Mexico), could not at once be put into successful operation there.  If also, as proposed, these duties are to be ascertained and collected as a military contribution through the officers of our Army and Navy, those brave men would more easily perform almost any other duty than that of estimating the value of every description of goods, wares, and merchandise.

The system of specific duties already prevails in Mexico, and may be put by us into immediate operation; and if, as conceded, specific duties should be more burdensome upon the people of Mexico, the more onerous the operation of these duties upon them the sooner it is likely that they will force their military rulers to agree to a peace.  It is certain that a mild and forbearing system of warfare, collecting no duties in their ports in our possession on the Gulf and levying no contributions, whilst our armies purchase supplies from them at high prices, by rendering the war a benefit to the people of Mexico rather than an injury has not hastened the conclusion of a peace.  It may be, however, that specific duties, onerous as they are, and heavy contributions, accompanied by a vigorous prosecution of the war, may more speedily insure that peace which we have failed to obtain from magnanimous forbearance, from brilliant victories, or from proffered negotiation.  The duties, however, whilst they may be specific, and therefore more onerous than ad valorem duties, should not be so high as to defeat revenue.