Brief Summary
The Set-Up
After being convicted of violating the Sedition Act at the close of WWI, Eugene Debs uses his public forum time of addressing the court to say #sorrynotsorry for being an idealistic, Socialistic, union-loving critic of the war.
The Text
After a stirring opening where he pledges his allegiance to the "meanest on earth"—he's talking about "mean" as in poor ("the lower class") as well as "mean" as in "nasty" ("the criminal element")—Debs remembers his boyhood and various examples of working class suffering that he witnessed as a union organizer.
He then goes on to marvel that a country as blessed as America could allow for so much hardship for so many; this is what has led him to adopt Socialism as his political philosophy. After explaining what Socialists believe, Debs expresses his confidence that capitalism is doomed because of the growing force of the Socialist movement.
Debs concludes with a poetic statement of how he sees hope for humanity just beyond the horizon.
Then he drops the mic and crowdsurfs out of court.*
*In our imagination.
TL;DR
Debs is going to jail and might well die there, but he's adamant that Socialism will win in the end.