Iowa Sen. Joni Ernst set to retire

• Republicans have been eyeing Rep. Ashley Hinson (R-Iowa) as a potential successor should Ernst choose to bow out.
• Hinson is expected to announce her run by the end of September, according to a person familiar with her plans.
• Iowa Rep. Zach Nunn (R), who was eyeing a bid for governor earlier this year, is not expected to jump into the race, the person said.

Between the lines: Ernst drew national attention — and a short-lived primary challenge — earlier this summer when her comments at a town hall touched off a firestorm.

• Ernst responded to a participant who asserted that "people will die" because of Medicaid cuts the GOP was pushing in Congress by saying, in part, that "we all are going to die."

• She issued a sarcastic apology the next day, saying she assumed everybody knows "we are all going to perish from this Earth" and that she's glad she did not have to bring up the tooth fairy as well.

Zoom out: A retired military officer, Ernst, 55, chairs the Senate's small business committee and was first elected to the chamber in 2014.

• CBS News was first to report her decision.