Abraham Lincoln was a Republican candidate for the United States Senate in 1858.
Abraham Lincoln ( [ ˈeɪbrəhæm_ˈlIŋkən ] February 12 , 1809 -- April 15 , 1865 ) was an American politician and lawyer who served as the 16th President of the United States from March 1861 until his assassination in April 1865 . In 1858 , while taking part in a series of highly publicized debates with his opponent and rival , Democrat Stephen A. Douglas , Lincoln spoke out against the expansion of slavery , but lost the U.S. Senate race to Douglas . The Lincoln -- Douglas Debates ( also known as The Great Debates of 1858 ) were a series of seven debates between Abraham Lincoln , the Republican candidate for the United States Senate from Illinois , and incumbent Senator Stephen Douglas , the Democratic Party candidate .