The sentence carries a tongue-in-cheek humor, hinged on political stereotypes often adopted in the American political landscape. A common stereotype and joke is the assertion within some circles that the Democratic party has mastered the art of "garnering votes from the dead," implying that they manipulate ballots to gain an unfair advantage. The sentence insinuates that the Trump Shooter, who, as the name suggests, was presumably a strong supporter of the Republican party, is now going to do exactly what is ironically and humorously attributed to the Democrat party - vote from beyond the grave.
The second layer of humor lies in the play of loyalties presented in the sentence. The Trump Shooter character, presumably a staunch supporter of President Trump and the Republican party, has suddenly transitioned to serving the interest of the very political party he would have otherwise opposed in his lifetime. This certainly adds an element of irony given we expect people to uphold their beliefs and loyalties even after death.
The third reason why this sentence might be considered funny is its audacious disregard for the sanctity of death. It merges an otherwise solemn subject – death – with the levity of political satire. Such juxtaposition is a common humoristic device as it pokes fun at serious affairs in a light-hearted manner.
The sentence itself is a crafted jest in the context of an old politically-inspired joke that has roots in American history. Historically, there have been instances where names of deceased individuals appeared on voting lists, primarily due to administrative errors. The joke has evolved over time into a sort of folklore, giving way to humor riding on political rivalry.
Further, the term 'Trump Shooter,' which does not specify whether it refers to a person supporting or opposing Trump, adds an additional layer of ambiguity and subtly enhances the humor. The twist at the end coalesces this ambiguity, unsuccessfully trying to use it as verification of voting fraud, making it ironic.
Lastly, the humor takes shape from the playfulness of the sentence structure and timing. The expectation is set up in the beginning regarding the presumed political alignment of the 'Trump Shooter.' The punchline delivered at the end, successfully subverts this expectation, heightening the irony and humor in the sentence. This surprise factor is a crucial element in comedy, and the sentence employs it effectively.
The Trump Shooter never even got to vote Republican but now that he s dead he ll be voting Democrat