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.

After the wipeout of 2016, I questioned whether Iowa’s top races of 2018 and 2020 would be foregone conclusions for the Republican incumbents. But amid unusually high turnout for a midterm election, Democratic challengers flipped two U.S. House seats and fell only a few points short against Governor Kim Reynolds and Representative Steve King.

One of my goals for 2019 was to provide in-depth reporting on Iowa’s federal and state legislative races. Thanks to our nonpartisan redistricting system, none of our four Congressional districts are considered safe for either party in 2020. While U.S. Senator Joni Ernst is still favored to win a second term, she is increasingly seen as a vulnerable GOP incumbent.

Follow me after the jump for a review of Bleeding Heartland’s coverage of the campaigns for U.S. Senate and House, with links to all relevant posts. A separate post will cover the year’s stories about battleground legislative districts.

Five Democrats are now competing for the chance to take on U.S. Senator Joni Ernst next November. After making low-key appearances at Democratic events around Iowa for about six months, Cal Woods made his candidacy official on December 17.

Assuming all five candidates file nominating petitions in March, the crowded field increases the chance that no one will win the nomination outright in the June 3 primary.

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?