Do you really believe that wanting to end slavery was a ‘radical’ idea?
Well firstly, Lincoln didn't want to end slavery. In his first inaugural address he called for the passage of the "Corwin Amendment" which would guarantee slavery indefinitely. Lincoln also did not end any slavery in areas under his control.
Secondly, in 1860, it was indeed a very radical idea to end slavery. Most people in the USA opposed slavery in 1860, but not at all for the reasons people nowadays think.
The reasons most people opposed slavery in 1850 were as follows.
1. They hated black people and they did not want them in their country.
2. They regarded "free labor" as an economic threat against their ability to work for income.
3. They hated wealthy people getting rich through slavery while they had to work for a living.
4. A very tiny minority thought it was morally wrong. These people were considered kooks at the time.
What makes the idea of ending slavery radical was that about 800 million of the 4 billion GDP was created by those slaves. US Government revenues were about 72% produced by slaves.
This is why Lincoln supported the Corwin amendment in an effort to keep the Southern states from leaving. Those states were supplying most of his revenue.