This Dust Was Once the Man

This dust was once the man,
Gentle, plain, just and resolute, under whose cautious hand,
Against the foulest crime in history known in any land or age,
Was saved the Union of these States

Walt Whitman

What is the word just most likely an allusion to?

Lincoln's career as a lawyer
Lincoln's death at war's end
Whitman's war reporting
Whitman's poem writingWalt Whitman

What is the "foulest crime in history"?

Creation of United States
Election of Pres. Lincoln
Civil War or slavery
Death or warfare