impressive rebound from a heart attack two months ago, and also his consistent slow climb in the polls. but they also emphasize a concern that his quiet rise is being overlooked. a democratic chairman in iowa tells the "new york times" the following. sanders is definitely being underestimated in iowa. part of his durability is he has 15 to 20% of the caucus who are absolutely committed to voting for him no matter what. that counts for a whole heck of a lot. cnn's ryan nobles has been covering the sanders campaign. ryan, what are you hearing from inside about how they feel and people around the campaign who feel this is maybe the right time to be on the rise? >> i have a text stream with annie creag who are helping me cover the campaign, and we were texting each other saying, this is what we've been saying for weeks, that the sanders campaign is a lot stronger than many people are giving them credit for. and what's interesting when you