Those who said war would follow the annexation of Texas were right. It was soon seen that Mexico would not sit down quietly under her loss of territory, or lightly pass over the affront to her national honor. They who reckoned on her doing so forgot that if the Spanish race is indolent, it is also brave.
When nations are resolved on war a pretext is soon found for it.
Texas had brought with her into the Union a dispute with Mexico about her western boundary. She claimed to the Rio Grande, while Mexico claimed to the Nueces,[1] thus leaving in question a tract one hundred miles wide, extending between these rivers.
It is true the tract itself was worth little to either party, it being mostly barren prairie land, but in a military view the Rio Grande offered much the strongest line of defence, and for this reason Texas wanted her boundary fixed on it.
A Spanish proverb says, "Force without forecast is little worth." Mexico was quietly massing troops along the Rio Grande, in the disputed territory, to be ready to fight, while sounding England to see if she would not help her against the United States. England was too wise to do so openly, but stood ready to take advantage of whatever the chance of war might throw in her way. As Mexico owed England money it was thought England would take California as soon as fighting began, both as security for the debt, and to get possession of a Pacific port, which we were preventing her from doing in Oregon, and would prevent in California. On the other hand, if war broke out, our Government had determined to take California itself and at once. So something more than a question of boundary was depending on war with Mexico.
If now Mexico had chosen to give up the boundary in dispute, without a fight, there is no telling how the decision might have affected the future of the United States. The question is perhaps, itself, the best apology we can find for the war.
The quarrel having thus become ours, troops were sent to the Lower Rio Grande to hold possession. The Mexicans brought forces to oppose them, and fighting began. After driving back the Mexicans at Palo Alto, and Resaca de la Palma, our forces crossed the Rio Grande into Mexican territory. General Zachary Taylor commanded on this line.
War being thus begun, steps were taken to push it by assembling an army of fifty thousand volunteers, and plans laid to invade Mexico at different points. In Generals Scott, Taylor, and Wool, we had able leaders, but the men they had under them were mostly new to war, being hastily levied and sent off into the field before they could be properly trained in the use of arms.
In the North the war was unpopular.[2] Its coming was foreboded and its consequences viewed with alarm. That section therefore looked on with indifference until the actual fighting roused the national spirit. Then the people, in general, heartily desired the success of our arms, though they still deprecated the war itself.
On the other hand, in the South, and particularly the South-west, the war was hailed with enthusiasm. The people there did not stop to inquire whether its aims were such as should control the acts of one powerful nation toward its weaker neighbor, but gave it unstinted support from the first. In Texas the war spirit was fully aroused by the promise of meeting her old enemy on more equal terms.
The war soon developed the larger issues we have pointed out. So though sometimes called "a little war," it is seen that the contest with Mexico was being waged for a large stake.
[1] The Nueces had been the acknowledged line between the provinces of Coahuila and Texas, before the latter achieved her independence, as shown by maps of the time.
[2] The War Unpopular. Placards calling for volunteers were posted in the streets, headed with the words "Ho for the Halls of the Montezumas!" The attempt of the administration party to kindle a war spirit, however, fell flat.
The regiment raised in Massachusetts was not even cheered when passing through the streets of Boston on its way to the front, and on its return home its flags were refused a place in the State Capitol.
But in Arkansas, Louisiana, Alabama and Mississippi the war fever ran so high that fifty thousand men could have been furnished by these States alone. In some districts the rush was so great that it was feared there would be too few whites left to keep the negroes quiet.