Riots at the DNC in Chicago, 1968. This kind of set the table for the creation of the Iowa Caucuses.
PBS History of the Iowa Caucuses (6 min)
Stephen Schmitt
Political Science teacher at Iowa State University. He has taught many classes on the Iowa Caucuses and has a good understanding of their origins. Here you will find the story about the Xerox machines.
The beginning talks about climate change and then transitions to history of the caucuses.
AUDIO INTERVIEW (1 hr, 7 min)
Can be found in Dropbox folder or you can click this link: https://www.dropbox.com/s/j3xq6had46iyz9g/Stephen%20Schmidt.m4a?dl=0
Articles attempting to explain the Iowa caucuses:
New NPR podcast about Iowa caucuses called "Caucus Land"
Each episode ~20 min. I just finished the six or seven episodes and it's fantastic! Lots of good material in there and it's fairly entertaining. Excellent for train or gym.