The latest Quinnipiac poll of Iowa:
Warren 20
Buttigieg 19
Sanders 17
Biden 15
Klobuchar 5
Harris 4
Buttigieg’s attack on Warren at the October 15 Democratic debate has clearly paid off for him. Since then, the RealClearPolitics average of Iowa polls has shown Buttigieg gaining about six points, Biden losing about six points, and Warren holding flat.