New York Times: “Caucuses are low-turnout affairs, making grass-roots organizing an essential factor for doing well in Iowa. Well-tooled campaigns depend on a paid field staff and armies of volunteers to identify supporters, ensure they turn out and provide leadership in the many school cafeterias and churches that serve as caucus rooms. But according to nearly a dozen county Democratic chairs and Biden activists around the state, Mr. Biden’s ground game has weak spots that threaten him with underperforming his polling in Iowa, where he has consistently been at or near the top.”

