Neither one. Lincoln got elected because he wanted to abolish slavery in all the non-state territories, that would eventually become states. I wrote this the other day about Lincoln's views and intentions toward slavery, so I'll quote again a few of the same words of Lincoln's from that previous response.

WHAT LINCOLN SAID BEFORE THE ELECTION

Remember that, in Lincoln's time, presidential candidates didn't openly campaign. It was all done through surrogates, speeches by Congressional supporters, as well as editorials by partisan newspapers. But Lincoln had already said plenty before the campaign started.

In his "A House Divided" speech of June 16, 1858, Lincoln talked of moving the slavery question to the point "where the public mind shall rest in the belief that it is in the course of ultimate extinction".

At the Sixth Lincoln-Douglas Debate on October 13, 1858, he said:

"I suggest that the difference of opinion [i.e., between Lincoln and Douglas], reduced to its lowest terms, is no other than the difference between the men who think slavery a wrong and those who do not think it wrong. The Republican party think it wrong; we think it is a moral, a social, and a political wrong. We think it is a wrong not confining itself merely to the persons or the States where it exists, but that it is a wrong in its tendency, to say the least, that extends itself to the existence of the whole nation. Because we think it wrong, we propose a course of policy that shall deal with it as a wrong. We deal with it as with any other wrong, in so far as we can prevent its growing any larger, and so deal with it that in the run of time there may be some promise of an end to it."

More succinctly, in a speech in Chicago on February 11, 1859, he told his audience:

"Never forget that we have before us this whole matter of the right or wrong of slavery in this Union, though the immediate question is as to its spreading out into new Territories and States."

He was constantly dog-whistling about the abolition of slavery. However, his immediate goal was always to end slavery in the territories, and that's what he got elected on.

THE PRESIDENTIAL CANDIDATES

Of the four major candidates in the 1860 election, Lincoln was by far the most progressive on the slavery question. Of the other three:

Stephen Douglas adopted a position that has been called the "Freeport Doctrine". It's called that because he first proposed it at the Second Lincoln-Douglas Debate on August 27, 1858, in Freeport, Illinois. The position was a modification of the "Popular Sovereignty" position he had espoused when proposing his Kansas-Nebraska Act of 1854. Under that act, he believed that the territories should have legalized slavery by default, but the territories could vote it out when drafting a constitution upon their application for statehood. The Freeport Doctrine was slightly more progressive. It was a "let the people of the territories decide right now" position. They should be able to vote it out immediately by popular referendum and/or by electing a territorial legislature that would outlaw slavery.

This position got Douglas in a lot of trouble within his party.^1 The reason it was controversial was that it ran contrary to the 1857 Dred Scott v. Sandford Supreme Court decision, which had decided Congress couldn't outlaw slavery in the territories. After that decision, Southerners believed they had a constitutional right to bring enslaved people into any U.S. non-state territory without interference, and they wanted that right upheld.

Douglas's position, which became the position of Northern Democrats, split the Democratic Party at their convention in Charleston in late April/early May 1860. Douglas was the front-runner, but after 57 ballots, the convention was at a stalemate between North and South and was threatening to turn violent. The convention was abandoned, and there was a second convention in Baltimore, in June. The Southerners pretty much immediately walked out, when Douglas continued to be the front-runner. The Southern Democrats held their own convention across town (more below).

John C. Bell was the Constitutional Unionist Candidate and his position was "the constitution as it is, the union as it is". This was basically a way of stating that the Dred Scott decision should be strictly adhered to. The Supreme Court said that Congress couldn't outlaw slavery in the territories, so the federal government should uphold that. Slavery should be legal in all the territories, though perhaps they could outlaw it on application for statehood, as the Kansas-Nebraska Act had previously proposed.

John C. Breckinridge and the Southern Democrats took a hard-line position to the slavery question. Not only should the Dred Scott decision be upheld, but it followed that Congress had a duty to enact a "slave code" in the territories. That is, a series of laws to regulate how slavery should be enforced there. Some Southern Democrats even thought this should include a federal "slave code" in regards to how slavery should be enforced in the free states, i.e., a stronger "Fugitive Slave Act" and more accommodating laws for "slave transit" (bringing enslaved people into free states for business, such as to help transport their plantation cargo to ports, etc.).

As mentioned, Abraham Lincoln, in contrast to the above, wanted slavery outlawed completely in the territories. This completely ran contrary to the Dred Scott decision. And while he never really said how this would work in practice, he as president would have veto power over any statehood application, so, at the very least, he could prevent any new state being entered into the Union as a slave state. That included Kansas, which had two competing constitutions being proposed in Congress, one pro-slavery and the other anti-slavery. (Kansas was entered into the Union as a free state after secession had begun, which Buchanan signed into law, but this was after the 1860 campaign had ended.) As far as enforcing a no-slavery-in-the-territories policy that Lincoln wanted, that may have proven more difficult.

There was no scientific polling back then, but Lincoln very much considered this plank of the Republican Party platform to be the plank that got him elected. There were editorials written about the expansion of slavery in the territories throughout the campaign by the Northern press. Republican papers very much supported Lincoln's position. Northern Democratic papers supported Douglas's. Southern papers supported one of the two Southern candidates. Slavery's expansion was the most-discussed issue of the campaign.

THE REPUBLICAN NOMINATION

To the second part of your question, about Lincoln being "moderate", he certainly wasn't a moderate in the general election. As far as getting the Republican nomination at the party convention, that may have been more true. Of the other front-runners for the nomination:

William Seward, U.S. Senator from New York, was widely recognized before the convention as being the favorite. However, he was viewed as too extreme (ironically, once the election was over and secession began, he proved to be much more conservative than Lincoln). This is because of many statements he had made in the years and months before the convention. He had been much more open in his intent of moving toward abolishing slavery than Lincoln had ever been, who played his cards much closer to his chest. Seward's most famous speech was entitled "The Irrepressible Conflict", in which he stated:

"[The collision between North and South] is an irrepressible conflict between opposing and enduring forces, and it means that the United States must and will, sooner or later, become either entirely a slave-holding nation, or entirely a free-labor nation."

Lincoln had said as much in his "House Divided" speech, though it wasn't quite so straightforward. Back in 1857, in reaction to the Dred Scott decision, Seward had given a speech on the Senate floor, directed at his Southern colleagues, in which he said:

"The interest of the white races demands the ultimate emancipation of all men. Whether that consummation shall be allowed to take effect, with needful and wise precautions against sudden change and disaster, or be hurried on by violence, is all that remains for you to decide."

Now that was more blatant than anything Lincoln had said before the election, and it was statements like these that got Seward painted as an extremist. The political boss of New York, Thurlow Weed, actually convinced Seward to take an extended tour of Europe in the months leading up to the convention, in the hopes that it would allow him to stay out of the fray, and perhaps might get Southerners to cool down about him. This backfired, because Lincoln was able to lobby his partisans among the Republican National Committee to get the convention held in Chicago, Illinois, his home state. The party chairman of the state was also able to arrange the floor, and put the "swing state" delegations in the vicinity of the Illinois delegation, while surrounding the New York delegation with "safe states" for Seward already. In his book Lincoln and the Election of 1860, historian Michael S. Green cited this as helpful in getting Lincoln the nomination, since it allowed for immediate horse-trading back and forth with the delegations that Lincoln needed in order to win.

So, while Lincoln was able to make direct communication with the people he needed to convince in the months leading up to the convention, Seward couldn't do anything directly. It was all handled through his surrogates, and outside of New York, there was distrust of Thurlow Weed, who proved to be ineffective.

(cont'd...)