Late last week, U.S. Senator-elect Joni Ernst finally sent Governor Terry Branstad a letter resigning her seat in the Iowa Senate. The governor announced today that the special election to replace Ernst in Iowa Senate district 12 will take place on December 30. The district covers six southwest Iowa counties; a detailed map is after the jump.

From a voter turnout perspective, it’s not ideal to hold an election between Christmas and New Year’s, when many people are out of town. However, the real competition in Iowa Senate district 12 will be at the GOP special nominating convention. Even in a low-turnout environment, there is almost no conceivable way Democrats could win a district containing more than twice as many registered Republicans. Just one state Senate district has fewer registered Democrats than Senate district 12, and only three contain more registered Republicans.

At least two Republicans will seek the nomination for the coming special election: State Representative Mark Costello, who was first elected to the Iowa House in 2012, and Fremont County Supervisor Cara Morgan. I expect more people to throw their hats in. A few years ago, a special election in an Ankeny-based Iowa Senate district drew six GOP candidates.

Any relevant comments are welcome in this thread. I was surprised it took Ernst so long to resign her state senate seat. Her predecessor Kim Reynolds resigned more quickly after being elected lieutenant governor in 2010.  

Iowa Senate district 12 includes Mills, Fremont, Montgomery, Page, Taylor, and Ringgold counties.