History of the War Between Mexico and The United States by Brantz Mayer

Origin of the war continued -- Proposed annexation of Texas to the United States by treaty -- Efforts of several administrations to recover Texas after the Florida treaty -- President Tyler's objects -- Mexican opinions -- British intrigue -- British views relative to Texas -- Defeat of the treaty in the senate -- French opinions.

There is no doubt that although the government of the United States was anxious to preserve a strict neutrality between the belligerents in 1837, and, thus, to avoid assuming the war with Mexico by annexing an insurgent State, it, nevertheless, refused the proffered union with regret. From the earliest period, our statesmen contended that, by the Louisiana treaty, we acquired a title to Texas extending to the Rio Grande, and that we unwisely relinquished our title to Spain by the treaty of 1819 which substituted the Sabine for the Rio Grande as our western boundary. [39] But, divested as we were by solemn compact with Spain, of what may have been our territory under the treaty with France, it was idle to regard Texas as a proper subject for restoration to the Union whilst active hostilities were waged by Mexico.