Once a political rock star, Cory Booker is now sinking in the Democratic mosh pit

FAIRFIELD, Iowa — Sen. Cory Booker seemed primed to take off in the Democratic primaries: He’s a black senator with bipartisan accomplishments, a Rhodes Scholar, a three-time former mayor of Newark, and a charismatic speaker with well over a decade of favorable media coverage under his belt.

Yet Booker is mired in the low single-digits in early Democratic primary polls, crowded out in a 23-strong Democratic field with political novices eclipsing him.