Lincoln was the second Republican ever to run for President and the first ever to win. The first, I believe his name was John Freemont (Something with "free" in it), lost largely because he was too radical with respect to the racial issues of the day. Read the Lincoln-Douglas debates, where Douglas charges:
"In 1854, Mr. Abraham Lincoln and Mr. Trumbull entered into an arrangement, one with the other, and each with his respective friends, to dissolve the Old Whig party on the one hand, and to dissolve the old Democratic party on the other, and connect the members of both into an Abolition party, under the name and disguise of a Republican party."
That's very early in a speech from the first debate at Ottawa, Illinois in 1858. This was the atmosphere of the time. Politics, especially at the national level, is about finding the center; it was true in 1992 with Clinton and the new term "triangulation" and it was true in 1852. Lincoln would have never been elected as a flat-out abolitonist; that would be like positioning yourself way to the left of Kucinich today. So Lincoln's statements could never get a pass today because our society, thankfully, has evolved past where his was. Here is an example of how, in his response, he lowers himself to the racism of the time and yet still clearly argues against the position that it was politically viable (possible) to assail, with any coments I felt necessary to add clearly separated by parenthesis:
I will say here, while upon this subject, that I have no purpose, directly or inderectly, to interfere with the institution of slavery in the states where it exists (the claim of Douglas's camp, playing on the fears that eventually led to secession). I believe I have no lawful right to do so (he wouldn't have), and I have no inclination to do so. I have no purpose to introduce political and social equality between the two, which, in my judgment, will probably forever forbid their living together upo the footing of perfect equality; and inasmuh as it becomes a necessity that there must be a difference, I, as well as Judge Douglas, am in favor of the race to which I belong having the superior position. I have never said anything to the contrary, but I hold that, notwithstanding all this, there is no reason in the world why the negro is not entitled to all the natural rights enumerated in the Declaration of Independence-- the right to life, liberty, and the pursuit of hapiness. I hold that he is as much entitled to these as the white man. I agree with Judge Dougla he is not my equal in many respects-- certainly not in color, perhaps not in moral or intellectual endowment. But in the right to eat the bread, without the leave of anybody else, which his own hand earns, he is my equal, and the equal of Judge Douglas, and the equal of every living man.
I have better examples of Douglas calling Lincoln out and interesting responses, which I can add later.
