Four candidates are polling well and drawing the largest crowds in Iowa ahead of the caucus

For the past several months, polling in Iowa has been pretty stable. There is a clear top tier of 4 candidates closely bunched at the top, with the rest of the field failing to move up. Dave Peterson, a professor and Whitaker Lindgren faculty fellow in political science at ISU, discusses this field of candidates and examines how they have campaigned as the caucuses draw near.