This is coolbert:
From a blog entry at the Internet web site isegoria.net an extract with my commentary:
The Mexican-American War of 1848 always a contentious issue.
"One of History’s Most Successful Aggressor Nations"
"The Mexican war: this was absolutely a war of aggression, but it was a war of aggression by Mexico against the USA. The various letters and communications between the American ambassador in Mexico City, the Mexican government, the Texan government, and Washington DC are absolutely fascinating reading and make it completely clear that Mexico was spoiling for a fight and finally got one. Polk and Slidell (the ambassador) went to quite a lot of effort to try to avoid war. Mexico was simply not willing to admit that Texas had actually beaten them and that they didn’t control it anymore. American troops in Mexico City was pretty much the only way to reconcile them to it."
The Republic of Texas having been incorporated into the Union that BORDER BETWEEN MEXICO AND THE UNITED STATES NEVER HAVING BEEN CLEARLY DEFINED AND AGREED UPON!!
The United States claiming the Rio Grande river as the border. Mexico claiming the Nueces river [further north of the Rio Grande] as the border. Between the two rivers there existing a no-mans land in dispute unresolved.
American troops having moved into the no-mans land and set up camp, raising the American flag, a casus belli? The Mexican responding with force, the American encampment attacked!!
Such was the war started!!
AMERICAN NEGOTIATORS IN THE AFTERMATH OF U.S. MILITARY VICTORY NOT ONLY RESOLVING THE BORDER CONFLICT BUT INCREASING THE SIZE OF THE UNITED STATES BY ONE-THIRD, THE ACQUISITION OF WHAT HAS BECOME KNOWN AS THE AMERICAN SOUTHWEST AS A RESULT.
Original source documents as cited in keeping with the Rankeian school of historiography.