U.S. Senator Chuck Grassley claimed this week that his grandson, Iowa House Speaker Pat Grassley, has “never expressed” interest in replacing him in the U.S. Senate.

Iowans haven’t voted out a sitting U.S. senator since 1984, but several recent events have caused political observers to question Senator Joni Ernst’s strengths going into her first re-election bid.

Inside Elections changed its rating on Iowa’s 2020 U.S. Senate race from “likely Republican” to “lean Republican” this month. (Sabato’s Crystal Ball already rated the IA-Sen race “lean R,” while the Cook Political Report still sees a GOP hold likely.) Writing at the National Journal on October 20, Josh Kraushaar cited several “major red flags suggesting Iowa is a much bigger battleground than Republicans anticipated at the beginning of the year.”

Ernst told supporters at a closed-door fundraiser with Vice President Mike Pence this month that she is the fifth most-vulnerable senator, according to Jennifer Jacobs of Bloomberg News.

What’s going on?