How many people in politics have a “half-glass-full mentality”?

“I think that the vice president is a person reflecting a half-glass-full mentality”

President Bush, In an NPR interview referring to Vice-President Dick Cheney (January 31, 2007)

Also, what is a “half-glass-full”? I’ve heard of a half-full glass, or a glass half-full, but never a half-glass-full.