From 1820 to 1850 , Jacksonian democracy began a set of reforms which included wider white male suffrage ; it led to the rise of the Second Party System of Democrats and Whigs as the dominant parties from 1828 to 1854 . The Trail of Tears in the 1830s exemplified the Indian removal policy that resettled Indians into the west on Indian reservations . The U.S. annexed the Republic of Texas in 1845 during a period of expansionist Manifest destiny . The 1846 Oregon Treaty with Britain led to U.S. control of the present-day American Northwest . Victory in the Mexican – American War resulted in the 1848 Mexican Cession of California and much of the present-day American Southwest
Trail of Tears
Trail of Tears
United States