Lincoln vs. the trend of the 19th century

Exactly what gives its real dignity to the figure of Lincoln is that he stands invoking a primitive first principle of the age of innocence, and holding up the tables of an ancient law, against the trend of the nineteenth century; repeating, 'We hold these truths to be self-evident; that all men are created equal, that they are endowed by their Creator, etc.,'

to a generation that was more and more disposed to say something like this: 'We hold these truths to be probable enough for pragmatists; that all things looking like men were evolved somehow, being endowed by heredity and environment with no equal rights, but very unequal wrongs,' and so on.

I do not believe that creed, left to itself, would ever have founded a state; and I am pretty certain that, left to itself, it would never have overthrown a slave state.

Source: What I Saw in America by G. K. Chesterton