Context


 * The **Monroe Doctrine** of 1823 defined United States foreign policy in the Americas for the rest of the nineteenth century and beyond. It declared that the United States had an interest in the Western Hemisphere and that European powers must not meddle in the affairs of any developing nations there. The United States was a young nation in 1823 and did not really have the power to back up the Monroe Doctrine. However, the policy was used to justify the sending of U.S. troops into Mexico in 1866 (to intimidate the French) and the purchase of Alaska in 1867.
 * The idea of **manifest destiny** gained popularity in the 1830s and 1840s. (The term was coined in 1845 by newspaper columnist John L. O'Sullivan.) As people began settling the western territories, wresting control of the land from the original Native American inhabitants, many Americans came to believe that it was their nation's "manifest destiny" to possess all of the North American continent. Later in the century, this idea easily gave way to larger dreams of expanding America's influence around the world.
 * By the late nineteenth century, the growing industrial economy of the United States was producing many more goods than the nation itself could consume. This**overabundance of industrial goods** led the United States to look for new markets abroad.
 * European nations such as England, Spain, France, Russia, Portugal, Germany, and Belgium had already carved up Africa and large parts of Asia into colonies and "spheres of influence" by the late 1800s. To remain competitive, the United States reacted to **European imperialism** by looking for a way to secure its own economic future through a policy of expansionism.