King, who's endorsed Sen. Ted Cruz (R-TX), suggested earlier Monday on MNSBC that Palin had been bought off, saying that Trump had wooed her with "assets" and "resources."
Palin responded to the charge while introducing Trump at a rally in Cedar Rapids, Iowa.
"It's dirty business but why would a conservative guy want to say something that he knows isn’t true?" Palin asked the crowd. "Maybe he’s forgotten some of his heart in the heartland. Maybe he’s been hanging out in a corn field too long huffing ethanol."
Palin goaded the crowd in saying that Trump did promise her one thing: he'll "make America great again."