Sen. Rick Gudex (R- Fond du Lac) surprised some when he retired after serving one term in the Senate. His retirement leaves an open seat and creates the best opportunity for a party flip this November.

The central Wisconsin district encompasses Oshkosh, Fond du Lac and Waupun and it has seen its share of close state Senate races.

In 2008, Republican Randy Hopper won the then open seat by 184 votes over Democrat Jessica King in a race where over 83,000 votes were cast. King then beat Hopper in the 2011 recall in another close race by a 51-49 percent margin. In 2012, Sen. Gudex knocked off the short-term incumbent King by 600 votes in a race with over 85,000 votes cast. Starting in 2017, the 18th Senate District will seat its fifth different Senator within a 10-year span. In contrast, over a third of the state will have seen one Senator during that time, with the vast majority having no more than two.

The candidate looking to take back the seat for the Democrats is current Winnebago County Executive Mark Harris. Harris recently ran unsuccessfully for the 6th District Congressional open seat against the eventual winner U.S. Rep. Glenn Grothman. While Grothman won the seat decisively, Harris carried his home county of Winnebago making him a strong candidate for the 18th District. 

There are two Republicans who have entered the race in an effort to hold the seat. Dan Feyen is a party activist and leader in the area who has worked for a printing company in Fond du Lac for nearly 30 years. He is facing off against Mark Elliott, a former pastor and current small business owner who lives in Oshkosh. In 2014 Elliott ran against sitting Democratic Assemblyman Gordon Hintz (D-Oshkosh) and came within about 700 votes. Insiders are split on who will emerge from the primary, as a case can be made for both candidates.

This seat remains the best opportunity for Senate Democrats to pick up a seat. Because of this, a lot of money will be spent on both sides in what could turn out to be another 18th Senate District nail-biter on election night.