Answer:
America's westward migration was affected by the notion of Manifest Destiny because it boosted the probability of that migration. It made America more likely to expand territorially.
According to the doctrine of "Manifest Destiny," Americans were generally superior to other people in a number of respects. They were claimed to have a superior religion, superior culture, and superior style of government. They were allegedly predestined by God to increase their area for these reasons.
The migration westward was influenced by this mentality. First, it contributed to the enlargement of US territory. It encouraged the idea that America deserved all of that land more than the Mexicans did, which contributed to the outbreak of the Mexican-American War. They believed it was acceptable to steal the territory from Mexico because it was part of America's divinely appointed destiny. As American settlers pushed west, they treated the Indians with the same mindset. Indians were supposed to be so beneath humans that they didn't deserve to live on the land. They were to be relocated, and the land was to be given to the Americans who earned it and would properly utilize it.
In these ways, the notion of "Manifest Destiny" contributed to the US's westward expansion.
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