White, less-educated, individuals who trend conservative (either on social values or economic policy); small-town, working class people; individuals with less than four years of college who earn less than 50K per year; religious, pro-gun, social conservatives.
Derived from Barack Obama's quote:
"You go into these small towns in Pennsylvania, and like a lot of small towns in the Midwest, the jobs have been gone now for 25 years and nothing's replaced them. And they fell through the Clinton Administration and the Bush Administration, and each successive administration has said that somehow these communities are going to regenerate and they have not. And it's not surprising, then, they get bitter, they cling to guns or religion or antipathy to people who aren't like them or anti-immigrant sentiment or anti-trade sentiment as a way to explain their frustrations."
"That's right, America: you can add Florida to the long list of Bitters forged in the crucible of the endless, violent, gnashing-of-teeth and rending-of-garments campaign of 2008." --Wonkette
"They have many Bitters in Michigan ever since the Chinese & Mexicans took their factory jobs." --Wonkette