VII
THE PRELIMINARIES OF THE CONFLICT
April, 1845—April, 1846
Strangely enough, although our diplomatic troubles with Mexico would almost certainly have led to hostilities, the war actually came about in a totally different way.[1]
During the spring and early summer of 1845, in view of Mexican threats and of reports from trustworthy sources that an invasion of Texas might he expected,[2] it was decided by our government that when her people should have accepted our annexation proposal, as they were almost sure to do, it would become the duty of the United States to defend her;[3] and this decision made the question where her southern boundary lay a practical matter. It was a thorny subject. In 1834 Mexico herself did not feel sure about the line; and according to the chief technical officer in our state department, sole commissioner to negotiate the treaty of peace with Mexico, if an official demarcation had existed, the war between Texas and the mother-country had rubbed it out. The former now claimed the territory as far as the Rio Grande, but she did not establish her title by occupying completely and effectively the region south of the Nueces. Only by an agreement with Mexico, indeed, could limits have been fixed. So far as it concerned the republic of Texas, this was in effect the situation.[4]
For the United States, however, this was not the whole story. Down to 1819 our government had insisted that Louisiana extended to the Rio Grande. In other language, since the southern part of Louisiana was called Texas, the official View was that Texas bordered on that stream. Such, then, was in effect the contention of Jefferson, Madison, Monroe, John Quincy Adams, Pinckney, Livingston and Clay,
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