In "Absentee," a powerful new Lincoln Project ad that runs nearly two minutes, Mark Hamill delivers a short course in American political history. The beloved actor reminds us all how absentee voting began during the Civil War as a way for Union Army troops to cast their ballots, far from home -- and how everything they fought to defend is at stake today.

"Nothing is more important than counting every vote, especially those that are serving our country. Suppressing any vote is un-American," says Hamill. If Trump gets his way and tosses out millions of absentee ballots, he warns, then many thousands of military absentee voters "will be deprived of their most sacred right.

"It cannot be allowed to happen."

Be ready to join Mark Hamill, the Lincoln Project, and millions of Americans to defend every ballot.