Abraham Lincoln (1809 - 1865) grew up in Kentucky and Indiana in a farming family, struggling to make a living in a wild, frontier nation. As there was little opportunity for formal education, he taught himself to read and write. The family moved to Illinois in 1830, where Lincoln worked as a rail splitter, store clerk, surveyor and lawyer.

Those who deny freedom to others, deserve it not for themselves;
and, under a just God, can not long retain it.
Messrs. Henry L. Pierce, & others. Springfield, Illinois. April 6. 1859

In 1834 he began the first of four terms in the Illinois legislature, while growing his law practice. Politically at that time he was a Whig, and campaigned vigorously for William Henry Harrison in 1840. The anti-slavery faction of the Whigs were absorbed by the Republican Party, and it was as a Republican that Lincoln first came to national attention, with a series of debates with his longtime nemesis Stephen Douglas.

Lincoln and Douglas were campaigning for one of Illinois' Senate seats, and agreed to seven debates throughout the state, which dealt primarily with the expansion of slavery into the new territories, something Lincoln vehemently opposed. Lincoln lost the election but was now a known entity on the national political scene, and on May 18, 1860, he secured the Republican Party nomination for the presidency.

A house divided against itself cannot stand. I believe this government cannot endure permanently half-slave and half-free. I do not expect the Union to be dissolved - I do not expect the house to fall - but I do expect it will cease to be divided. It will become all one thing or all the other.
"A House Divided": Speech at Springfield, Illinois June 16, 1858

The Democratic Party was fractionalized that year, and they split into the Northern Democrats, who nominated Stephen Douglas, and Southern Democrats, who nominated  John C. Breckenridge. A last party, the Constitutional Party, comprised of those who could not abide by either the Republicans or the Democrats, nominated John Bell.

The Republicans felt that although Lincoln was respected and admired by many, he needed to be more accessible as a personality. They highlighted his humble beginnings, with particular attention on his previous work as a rail splitter. Soon he was the "Rail Candidate."

Whenever I hear any one arguing for slavery I feel a strong impulse to see it tried on him personally.
Speech to One Hundred Fortieth Indiana Regiment March 17, 1865

The split among the rival parties proved beneficial to Lincoln. He earned less than forty percent of the popular vote, but due to his popularity in the more popular northern and free states, he was able to win an Electoral College majority.

It surprised no one that he won zero southern states; that winter several southern states seceded and declared themselves the Confederate States of America, and the Civil War began soon after.

I am rather inclined to silence, and whether that be wise or not, it is at least more unusual
nowadays to find a man who can hold his tongue than to find one who cannot.
Remarks at the Monongahela House, Pittsburgh, Pennsylvania February 14, 1861

The Union prevailed and Lincoln was re-elected in 1864, but was assassinated by John Wilkes Booth on April 14, 1865 while he attended a play in Washington, D.C.

Abraham Lincoln. (2009). In Encyclopædia Britannica. Retrieved November 05, 2009.
Abraham Lincoln Historical Digitization Project.
The Collected Works of Abraham Lincoln.
EDSITEment, National Endowment for the Humanities. Abraham Lincoln, the 1860 Election, and the Future of the American Union and Slavery.
The White House. Abraham Lincoln.