Answer:
by igniting debate over the expansion of slavery
Explanation:
Manifest Destiny refers to a 19th century idea that the American way of life and its institutions were special and had no equal in the world, and that the people from the United States had an almost divine mission to spread their values across the continent. This idea supported expansionism, especially towards the western areas of the North American landmass.
Manifest Destiny, however, was a deeply controversial idea, especially because of the division between northern industrial states and southern slave holding states. Northern states opposed the expansion of slavery, as they feared that every new territory added to the southern United States would tip the delicate balance between north and south. After the annexation of Texas in 1845 and the invasion and annexation of the northern territories of Mexico in 1848, public opinion gradually shifted towards opposition against Manifest Destiny, as it was now inevitably linked with the expansion of slavery. The north-south division grew over time, culminating in the Civil War (1861-1865).
