Happy Birthday, Abraham Lincoln.
I would characterize President Lincoln as one of two indispensable leaders we have been blessed to have had. The first was President Washington, without whom there would be no United States of America.
The second, and so far last, was Lincoln, without whom America would look far different (and worse) than it does.
As for “greatest?” Impossible to judge between Washington and Lincoln. And, fortunately for us, we don’t need to.