Abraham Lincoln (February 12, 1809 – April 15, 1865) was the 16th President of the United States, serving from March 1861 until his assassination in April 1865. He successfully led his country through a great constitutional, military and moral crisis – the American Civil War – preserving the Union, while ending slavery, and promoting economic and financial modernization. Reared in a poor family on the western frontier, Lincoln was mostly self-educated. He became a country lawyer, a Whig Party, Illinois state legislator in the 1830s, a one-term member of the United States House of Representatives in the 1840s, but he failed in two attempts to be elected to the United States Senate in the 1850s. After opposing the expansion of slavery in the United States in his campaign debates and speeches, Lincoln secured the Republican Party nomination and was elected president in 1860.