Claim: Abraham Lincoln was a leader in building the new Republican Party.

Abraham Lincoln -LRB- -LSB- ˈeɪbrəhæm_ˈlIŋkən -RSB- February 12 , 1809 -- April 15 , 1865 -RRB- 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 . Lincoln led the United States through its Civil War -- its bloodiest war and perhaps its greatest moral , constitutional , and political crisis . In doing so , he preserved the Union , paved the way to the abolition of slavery , strengthened the federal government , and modernized the economy .   Born in Hodgenville , Kentucky , Lincoln grew up on the western frontier in Kentucky and Indiana . Largely self-educated , he became a lawyer in Illinois , a Whig Party leader , and was elected to the Illinois House of Representatives , in which he served for eight years . Elected to the United States House of Representatives in 1846 , Lincoln promoted rapid modernization of the economy through banks , tariffs , and railroads . Because he had originally agreed not to run for a second term in Congress , and because his opposition to the Mexican -- American War was unpopular among Illinois voters , Lincoln returned to Springfield and resumed his successful law practice . Reentering politics in 1854 , he became a leader in building the new Republican Party , which had a statewide majority in Illinois . 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 .   In 1860 , Lincoln secured the Republican Party presidential nomination as a moderate from a swing state . Though he gained very little support in the slaveholding states of the South , he swept the North and was elected president in 1860 . Lincoln 's victory prompted seven southern slave states to form the Confederate States of America before he moved into the White House -- no compromise or reconciliation was found regarding slavery and secession . Subsequently , on April 12 , 1861 , a Confederate attack on Fort Sumter inspired the North to enthusiastically rally behind the Union . As the leader of the moderate faction of the Republican Party , Lincoln confronted Radical Republicans , who demanded harsher treatment of the South , War Democrats , who called for more compromise , anti-war Democrats -LRB- called Copperheads -RRB- , who despised him , and irreconcilable secessionists , who plotted his assassination . Politically , Lincoln fought back by pitting his opponents against each other , by carefully planned political patronage , and by appealing to the American people with his powers of oratory . His Gettysburg Address became an iconic endorsement of the principles of nationalism , republicanism , equal rights , liberty , and democracy .   Lincoln initially concentrated on the military and political dimensions of the war . His primary goal was to reunite the nation . He suspended habeas corpus , leading to the controversial ex parte Merryman decision , and he averted potential British intervention in the war by defusing the Trent Affair in late 1861 . Lincoln closely supervised the war effort , especially the selection of top generals , including his most successful general , Ulysses S. Grant . He also made major decisions on Union war strategy , including a naval blockade that shut down the South 's normal trade , moves to take control of Kentucky and Tennessee , and using gunboats to gain control of the southern river system . Lincoln tried repeatedly to capture the Confederate capital at Richmond ; each time a general failed , Lincoln substituted another , until finally Grant succeeded . As the war progressed , his complex moves toward ending slavery included the Emancipation Proclamation of 1863 ; Lincoln used the U.S. Army to protect escaped slaves , encouraged the border states to outlaw slavery , and pushed through Congress the Thirteenth Amendment to the United States Constitution , which permanently outlawed slavery .   An exceptionally astute politician deeply involved with power issues in each state , Lincoln reached out to the War Democrats and managed his own re-election campaign in the 1864 presidential election . Anticipating the war 's conclusion , Lincoln pushed a moderate view of Reconstruction , seeking to reunite the nation speedily through a policy of generous reconciliation in the face of lingering and bitter divisiveness . On April 14 , 1865 , five days after the surrender of Confederate commanding general Robert E. Lee , Lincoln was assassinated by John Wilkes Booth , a Confederate sympathizer .   Lincoln has been consistently ranked both by scholars and the public as among the greatest U.S. presidents .