Seward Attack

[Laurie Verge]

At some point, Booth had to have learned from someone - or knew it anyhow - the political point that made killing Seward key to the whole idea of throwing the Union into chaos. The Secretary of State would be needed to call for the special election in the event of both Lincoln's and Johnson's deaths. Without Seward, it would delay getting leadership even longer, etc.

I just have to suspicion that at some point between it becoming obvious that Richmond could not be held and the final surrender, Booth was either instructed or knew to do it on his own to eliminate Lincoln, Johnson, and Seward -- and even Grant, who was still in charge of military forces. I would bet on Judah Benjamin or George Sanders having been Booth's political science instructor(s).