Right, McGrath. And it all comes down to the chorus:

Mr.Lincoln, I wish you were here The Republic's changed a lot in a hundred years And I don't think it's working like you planned Oh Mr.Lincoln, we sure could use a hand

It IS Lincoln this was addressed to, it IS referring to changes made a hundred years ago (when did Junior write this) and not a hundred plus four score, to get back to the framing of the constitution and the time "the Republic" was established [events which did not have any personal involvement by Abraham Lincoln, who wasn't born for another thirty years}. Then comes the kicker: "I don't think it's working like you planned"...not Washington or Jefferson or Madison, "you planned" means Lincoln planned. The final line means "we wish you could come back and, realizing that it was wrong, undo what you did."

Although Lincoln didn't campaign as an abolitionist, he was a free stater: He wanted no more slave states in the union, and as soon as he was elected the slave states got the message: a few more free states and the anti-slavery North would have the votes to change the constitution to eliminate slavery (which even Imperial Russia had abolished a few years before). Slavery was the causus belli of the war.

--seed

P.S. As far as the quality of the song is concerned, it's a melange of weak rhymes and broken rhythms, and hasn't one memorable idea or image. Sorry, guys.