Was the US justified in going war with Mexico?

Answer 1

It was not; the Thornton Affair happened in the Nueces Strip which was disputed territory and should have been sent to arbitration.

The truth is, James K. Polk wanted California at all costs (see related questions) and offered to pay for it at first. When Mexico refused to sell, he looked for any pretext to start a war; he got away with it. An unintended consequence however, was the status of acquired territories and slavery. This ultimately led to the American Civil War.

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It would be very wise indeed to take a close look at the wording of this sentence. The question stands on its own, without context. Therefore, on the surface, it seems to ask for a historically honest and objective evaluation of the causes of the Mexican-American War.

However, the question is itself not historically objective. The person who asked it presumes that the US was unjust and wrong, which is an opinion. When searching for answers about a historical event, a diligent historian will find, read, and analyze all the available evidence recorded by those who took part in the event. After that, he or she will examine everything available written about the event at the time. Next, the historian will review what other historians have written about it: their conclusions, interpretations, sources, and analyses. Only then can the conscientious historian defend such an opinion.

The easier approach is to form an opinion first and examine only the evidence that supports it. In this case, a researcher seeking an unbiased answer might ask, "How did the US justify going to war with Mexico?" or, "Why do some people say the US was unjustified in going to war with Mexico?"

*Note: This observation makes no judgement or comment on whether or not the Mexican War was justified.

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To the last commenter above: Indeed you would be an excellent politician. Not only you didn't elaborate on the answer, but also provided lots of 'verbiage' that add nothing to the answer, just giving clues that you disapprove.

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I hope I make a better public historian, which is my chosen profession. I neither approve nor disapprove of the historical conflict or the original answer, as noted. Nor did I intend to elaborate on it. But students need to understand how the phrasing of the research question can profoundly influence the direction and conclusion of the study (i.e., the answer). Exactly the same way as opinion polls can be engineered to reflect the desired outcome. Since the answer mirrored the question's assumption and offered no evidence, it seemed wise to provide a grain of salt and help students learn to disassemble the messaging they receive. That's all. If there any more questions, please send me a PM or start a discussion thread. Thanks, and be well...

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The US had every right to view Mexico as a threat. Mexico was led by the dictator Santa Ana. His policies on borders that existed between the US and Mexico became a threat to US security. The US war against Mexico and its ultimate victory have been and were at the time justified.

Answer 2

It was a movement that looked for expansion throughout the American continent at the expense of non-whites. At the end, it was also the reason of the American Civil War.

Answer 3

As a totally unbiased and independent observer, it seems to be a case of blatant stealing of Mexican land by the US government under President Polk.