What did the idea of Manifest Destiny mean?
That all U.S. expansion was just and inevitable.
From the earliest days of America's existence, it was known that expansion westward was inevitable. The 18th and more 19th century belief was that all expansion was a good thing, just and moral.
Manifest Destiny meant a lot when it was first adopted by the scores of settlers moving West.
Manifest Destiny arose out of several factors in 1800s America:
- The Second Great Awakening, a period of renewed spiritualism in America, where people felt God had more influence in their lives and the destiny of the country.
- Territorial acquisitions, the major one being the Louisiana Purchase of 1803 which doubled the size of the U.S.
- A growing feeling of nationalism and autonomy (don't take too much from this point though, because you could easily say America was becoming less nationalistic). I say a "growing" feeling of nationalism/autonomy because of the Monroe Doctrine, which essentially told European nations to go away and stop messing with America's business.
The first of these two, in my opinion, formed the foundation of Manifest Destiny. The Second Great Awakening gave Americans a spiritual boost, and convinced them that with God's divine assistance, anything was possible for the young nation. The territorial acquisitions gave a further justification - America, after all, had a lot of land in the late 1800s, when Manifest Destiny became popular, and who else but Americans could settle it?
The Manifest Destiny, back then, meant just about everything to the pioneers and settlers. They justified their expansion out west on the concept of Manifest Destiny - i.e., that God was giving them the right to settle on the empty land in the West. If God was allowing them to do this, the settlers thought, it was perfectly okay.
Today, in an age based upon reason more than religion, we might like to think that Manifest Destiny is another example of people justifying often violent actions (the stealing of Native American land by white settlers, as Manifest Destiny encouraged), but then we would be projecting modern ideas to the past. To understand history, we must look at things from our ancestors' perspectives - not from our perspectives.
So, to summarize, Manifest Destiny really meant more to people of 1800s America than we may think. They based some of their most important life decisions off this idea, and in doing so they grew America to the large and populous country it is today.