This is a practice essay I wrote for the AP U.S. History exam. It's for the first free response section, in which your shown 10 historical documents, and then asked to incorporate those topics into an essay on a certain subject. 15 minutes are provided for reading and planning, and 30 for writing.

"Manifest Destiny was a driving force in 19th century politics. The belief that it was the United States duty, even destiny, to spread Freedom and Democracy throughout North America shaped both Public and Foreign policy. It led to war with Mexico, and even inadvertently led to the Civil War.

It is clear that Manifest Destiny was a widely accepted and widely defended view. Various Presidents used it to gain new territories and to follow their own agendas. But politicians weren't the only ones to embrace Manifest Destiny. Celebrated writer Walt Whitman enthusiastically proclaimed the United States mission to "People the New World with a noble race" in an editorial in the Brooklyn Daily Eagle. John O'Sullivan, another 19th century writer, penned a book entitled "Manifest Destiny" in which he stated that the United States was "The Nation of human progress" and that no earthly power could put a stop to its onward march.

Such lofty views and ideas were very beneficial to the U.S., but Mexico, the United States more volatile neighbor, suffered from them. Manifest Destiny is part of what drove the Mexican-American War, which the U.S. profited from, greatly. Although President Polk claimed that the war was because of "A long-continued series of menaces" and the shedding of American blood on U.S. soil, the desire for new land, such as California, was also a great factor. California had little to do with the rest of Mexico's and the United States's relations, so it's seisure during the Mexican-American War undermined President Polk's claims.

This did not go unnoticed. In 1848, Abraham Lincoln's "Spot Resolution" called on Presidetn Polk to answer questions about the validity of the Mexican-American War "Fully, fairly, and candidly". He also questioned the claim that American blood was first spilled on U.S. soil.

Lincoln's involvement in the "Spot Resolution" foreshadowed a greater consequence of Manifest Destiny, the Civil War. Acquiring new territories was all well and good, but deciding what to do with them afterward proved to be a greater difficulty. The main issue surrounding new states was whether or not to make them slave states. The conflict over slavery versus nonslavery in new states eventually lead to the creation of a new political party, the Free Soil Party. Not all results of slavery tension were so benign, however. The Bleeding Kansas affair shocked many citizens, but it was only a small example of what was to happen in the Civil War.

So despite all the lofty views Manifest Destiny first espoused, it eventually led to one of the bloodiest and grimmest events of American History, the Civil War. This proves that even the noblest of intentions can go wrong, in the long run."