The Office of Commissioner of Insurance was created in 1870 but did not become an elected office until 1881.
Candidates' party affiliations obtained from the 11/4/1881 Iowa County Democrat. https://chroniclingamerica.loc.gov/lccn/sn86086852/1881-11-04/ed-1/seq-1/
Source for Popular Vote data: Wisconsin Board of State Canvassers, "Commissioner of Insurance," Tabular Statement of the votes...at the General Election (Madison, 1881)