"I'm not convinced there's a steep erosion of support here," said G. Terry Madonna, director of the Franklin and Marshall College Poll. "Some of those voters may have gone from strongly to somewhat in terms of support. But I think he's held on to much of his base, and we know who they are. They're white. They're generally described as working class with a high school education or less and with a family income of $50,000 to $60,000."