Students will be able to identify wars and conflicts that the United States was involved in from 1800-1980. Background The United States was involved in various international conflicts as well as wars within its border. Between 1812 and 1815, the United States fought Great Britain in the War of 1812. In 1836 came the War of Texas Independence. The Mexican-American War was fought from 1846 to 1848. Shortly after, the United States went to war with itself over the issue of slavery, with Union and Confederate forces fighting from 1861-1865. Throughout this time, and particularly after the Civil W Duration: 30 Minutes.