Interpreting Primary Sources
Our manifest destiny [is] to overspread the continent allotted by Providence for the free development of our yearly multiplying millions.
John L. O'Sullivan, 1845
Texas has been absorbed into the Union as the inevitable fulfillment of the general law which is rolling our population westward....It was disintegrated from Mexico in the natural course of events, by a process perfectly legitimate on its own part, blameless on ours....
California will, probably next fall away from...Mexico...imbecile and distracted...The Anglo-Saxon foot is already on its borders....All this without agency of our government, without responsibility of our people--in the natural flow of events, the spontaneous working of principles....
Democratic Review, 1845
Mexico has passed the boundary of the United States, has invaded our territory and shed American blood upon American soil. She has proclaimed that hostilities have commenced and that the two nations are now at war.
As war exists, and, notwithstanding all our efforts to avoid it, exists by the act of Mexico herself, we are called upon by every consideration of duty and patriotism to vindicate with decision the honor, the rights, and the interests of our country.
Polk's War Message, 1846
How does it become a man to behave toward this American government today? I answer that he cannot without disgrace be associated with it. I cannot for an instant recognize that political organization as my government which is the slave's government also.
Henry David Thoreau
Now we ask, whether any man can coolly contemplate the idea of recalling our troops from the [Mexican] territory we at present occupy...and...resign this beautiful country to the custody of the ignorant cowards and profligate ruffians who have ruled it for the last twenty-five years? Why humanity cries out against it. Civilization and Christianity protest against this reflux of the tide of barbarism and anarchy.
New York Evening Post, 1848
Have not results in Mexico taught the invincibility of American arms?...The North Americans will spread out far beyond their present bounds. They will encroach again and again upon their neighbors. New territories will be planted, declare their independence, and be annexed. We have New Mexico and California! We will have Old Mexico and Cuba! The isthmus cannot arrest--nor even the Saint Lawrence!! Time has all of this in her womb. A hundred states will grow up where now exists but thirty.
DeBow's Commercial Review, 1848
Questions To Think About
1. Define "manifest destiny." What forces contributed to the commitment to American expansion?
2. Why did the United States go to war with Mexico?
3. How does President Polk justify an American declaration of war against Mexico? Do you find his explanation convincing?
4. What were American motives for waging the war?
5. Why did opponents oppose the war?
6. What were the political consequences of the Mexican War?