Question about How North America was created?

Someone please explain something to me. This is a question that has puzzled me for a very long time. When the forefathers of this land first went to war with the Natives, they managed (by whatever means) to take all of North American from them a little at a time. Everything from the Great North which later became Canada, to the far South which was built by Slave Labor, every piece of desired land was eventually taken.

My question is…Why did the Government stop at the Rio Grande river? What stopped it from invading Mexico?

I believe that California, New Mexico, Navada and Texas all at one time were parts of Mexico and were taken by the U.S., but what did the Mexicans have or do that stopped the U.S dead in its tracks right at the Rio Grande River? Anyone know?

I believe the annexation of all of Mexico was proposed by some after the Mexican War. The considerations that prevented it were in part: (1) Unlike the other colonized/conquered territories which were relatively sparsely inhabited, the southern parts of Mexico had a very large, mostly non-white, non-Protestant population. This population would have been very difficult to assimilate or subject to U.S. rule, and their inclusion in the U.S. would have vastly changed the character of the country. (2) Much of Mexico would have been suitable for cotton cultivation and thus slave labor. Northern, anti-slavery states did not want to annex so much area that would have potentially formed new slave states.

California was annexed because it was highly desirable fertile land. The more desolate intervening territory (New Mexico, Arizona, etc.) was taken largely because it was in between. The desert parts of northern Mexico were not considered to be worthwhile because much of their mineral wealth was not yet realized.


Of all the answers that I’ve received over the past few years, YOUR ANSWER is the best and most sensible one so far.

                          Thank you (and I mean that sincerely) 


You’re welcome.

I did some more checking of sites, and it seems that John C. Calhoun, a slavery supporter, strongly opposed annexing Mexico south of the Rio Grande specifically because he didn’t want to have to give Mexicans the vote. So not everyone who was pro-slavery supported annexation of all of Mexico.

From the thread title I thought this would be a question about plate teutonics. Boy was I wrong!

Got a bit of an axe to grid, have we? This is GQ, not GD, so I’ll try to answer your question as such.

First, let’s clear up some misconceptions and give you some much needed historical background. When the Spanish, Portuguese, French, English, and to a lesser extent the Dutch and the Russians started colonizing the Americas, they all had to deal with the Natives in some way or another. In Central and South America, there were large, advanced civilizations (Aztecs and Incas, respectively, plus numerous other smaller groups). The Spanish basically conquered and enslaved these civilizations. In what is now the US and Canada, no such advanced civilizations existed, just scattered, nomadic tribes. As more and more European settlers (primarily English and French) arrived, those tribes kept getting pushed further and further west. At the same time, the Spanish were extending to the North from their power base in Central Mexico to control California, Texas and New Mexico.

Flash forward about 200 years. The US, now independant of England is still pushing westward, filling in the land acquired in the Louisiana Purchase. Also, many pioneers from the US are moving into Texas and California (now belonging to Mexico, also newly independent from Spain) seeking desirable land. By this point the Natives were not much of an issue, pretty much relegated to living on reservations, with little choice but to accept whatever the US government was willing to give them. You can argue that they got a raw deal, but this forum is for factual answers, not debates.

Okay, now for the answer to your question: Why didn’t the US take over all of Mexico? Well, it wasn’t for lack of trying. Remember the settlers from the US who were moving into Texas? Eventually, they started outnumbering the “locals” (who were in turn descendent from the earlier Spanish settlers). Dissatisfied with being under Mexican rule for various reasons, Texas broke away from Mexico in the 1830s. The US played no part in this war. Eventually a watchful peace (to borrow a phrase from Tolkien) emerged, with Mexico sort-of-but-not-really acknowledging the independence of Texas. Texas petitioned the US for annexation, but not wanting to risk war with Mexico, the US declined. Texas instead declared itself an independent republic. Mexico never formally recognized their independence, and the area between the Rio Grand and Sabine Rivers was disputed territory.

During the US presidential election of 1844, James Polk promised to annex Texas, settle the Oregon question (the territory was disputed with Great Britian), and to purchase California from Mexico. Polk won the election by a landslide. Seeing the writing on the wall, the outgoing president, John Tyler, signed the bill to annex Texas before leaving office. US troops under the command of Zachery Taylor were sent to fortify the Texas border, specifically the disputed area between the Rio Grande and Sabine Rivers. Mexican forces attacked those troops, and the US-Mexican war began. It lasted from 1846-1848. US settlers in northern California took the opportunity to declare their own independence from Mexico, but that only lasted about a month before US forces showed up and placed the area under military jurisdiction. Eventually, US forces occupied all of California and New Mexico territories.

Eventually US Marines landed near Vera Cruz, pushed their way inland, and captured Mexico City. Polk sent diplomats to negotiate a peace treaty. Due to the disarrayed state of the Mexican government, there was no one to negotiate with them. Polk eventually recalled the diplomats, and intended to continue the war. However, in the intervening time between Polk issuing the recall order and that order arriving in Mexico City, the Mexican government got their act together and negotiated a peace treaty that ceeded all of Texas, California, and New Mexico in exchange for $15 million. Polk had no choice but to submit the treaty to the US Senate, who ratified it, ending the war and nearly doubling the size of the US.

So the answer to the question is they tried, and nearly succeeded.

One small quible with Max_Castle’s answer. Yes, U.S. Marines played a part in the beachhead at Vera Cruz, but it was a U.S. Army under Winfield Scott that took the city and eventually Mexico City itself. the marines were just a small part of this force.

BTW, a lot of the major military names in the Civil War were young officers in Scott’s campaign, including Lee, Jackson, Johnston, Meade, Grant and proabably a bunch more i can’t think of off of the top of my head. Scott used indirect assaults to beat Santa Anna’s napoleanic tactics time and time again even though the Mexicans usually had a 3 or 4 to 1 advantage in troop numbers.

Another correction to my post: Replace all mentions of the Sabine River with the Nueces River. The Sabine River is the border between Texas and Louisiana.

Also, I meant to mention that all of this information is readily available in any reputable book on US history.

Prior to European contact, the overwhelming majority of Native Americans were most definitely not nomadic. Nomadic lifestyle only became the rule rather than the exception in some parts of the plains states after the introduction of the horse. Most tribes were highly fixed in location, grew crops, built cities, etc.

The Chinook people of the Pacific Northwest are considered to have been one of the “wealthiest” stone age people ever. The richness of the land and sea provided a very high standard of living given their technology. They built two story houses with balconies on hills overlooking the Columbia river that early explorers initially mistook for European homes. Lewis and Clark visited a city of Chinooks during their explorations. That city was located near where the Portland Airport is. It had from 10,000-20,000 residents. By the 1840s it was deserted. Disease wiped out nearly all the Chinooks within a few decades.

The large nations of the SE US were also complex, corn growing societies. The rule of kings could extend for a hundred miles. After the early Spanish explorations, they too essentially vanished due to disease.

By the time settlement began in many areas, the land had only a fraction of the original population and many times there were new tribes that had already moved in and settled for some time. (But still not as well populated.)

Note that the Spanish had a huge head start in Mexico. Almost 100 years. California, Texas, and Florida were fringe areas that in many cases were not as easily settled for the type of farming that the Spanish settlers were looking for. Spanish populations in those areas were increasing over the centuries, but a lot slower than the population in the developing US. (Spanish vs. American land owning policies also affected this a lot.)