Aaron Neville sings: "poor farmer's land." It's on his album Warm Your Heart - some good stuff on there, though some of it gets a little too syrupy for cynical Brit palates.
I gather "cracker" is a term similar to "po' white trash" - directed at Southern poor whites, though I stand to be corrected and I'm sorry if I give offence.
I can't see any reason why Neville shouldn't use it - after all, it's not as if it would be seen as his opinion. The words are put into Coolidge's mouth, to give an impression of what he thought of the people there.
But I suppose some folk may only half-listen, and think he was using the word himself. It wouldn't be the first time a Randy Newman song had got into trouble through not being listened to properly - remember Short People?