BUSHMAN
In S2E21, "Fore, Father," we see that this is Quagmire's vanity plate. Rhode Island is actually one of the bluest of the blue states, and few residents would be caught dead voting for anyone named Bush. In the most recent election before this episode (2000), Rhode Island had the lowest state percentage of votes for Bush, 32%. Oh, yeah!
By the way, the idea that the "BUSH" in BUSHMAN might refer to anything other than the forty-first or forty-third Presidents of the United States never even crossed our minds. So please stop sending pictures of your lady business to stuffie@quahog.org.