In an interview with Bloomberg News, Iowa Senator Joni Ernst warned the public that should Joe Biden win in the elections, the Republicans can simply impeach him over his work in Ukraine.
The senator stated that there are grounds for the impeachment, and that would be for "being assigned to take on Ukrainian corruption yet turning a blind eye to Burisma because his son was on the board making over a million dollars a year." That was when then-president Barack Obama sent Biden on his behalf to fight corruption. That ended up in the removal of prosecutor general Viktor Shokin, who said that he was fired because he was the one investigating Burisma and Biden wanted to protect his son.
The Republicans were worried about this move back then and are now considering this as grounds for impeachment.
The first term Republican told the interviewer
"I think this door of impeachable whatever has been opened. Joe Biden should be very careful what he's asking for because, you know, we can have a situation where if it should ever be President Biden, that immediately, people, right the day after he would be elected would be saying 'Well, we're going to impeach him'."
Joe Biden, on the other hand, claims Ernst's words were a threat and implies that it is President Donald Trump's motive to damage his candidacy and that the Republican party is behind it. He told Iowa crowds that "You can ruin Donald trump's night by caucusing with me and ruin Joni Ernst's night as well." He continues to tell people that this was all the plan from the beginning, to not run presidency against him.
To reinforce that sentiment, Biden's campaign communications director Kate Bedingfield is encouraging Iowans to caucus for Biden, saying “Iowans have the chance tomorrow to say the words that Donald Trump and Joni Ernst fear most: I’m here to caucus for Joe Biden."