"Ernst, who maintained she is remaining neutral in the race, will be introducing Rubio at an event in Des Moines...
"As I have made clear, I will not be endorsing in the caucuses; that is a promise I will maintain to Iowans," Ernst continued. "On Monday, I look forward to introducing Marco to more Iowans and discussing the important work needed to keep our nation safe and secure."
Way to stay neutral, Joni.
Subnote: the major newspaper in IA, the Des Moines Register, has endorsed Rubio and Clinton.
http://www.cnn.com/2016/01/23/politics/des-moines-register-endorsements/