Wisconsin Constitution
Article VII - Judiciary
Section 4 - Supreme court: election, chief justice, court system administration.

1. The supreme court shall have 7 members who shall be known as justices of the supreme court. Justices shall be elected for 10-year terms of office commencing with the August 1 next succeeding the election. Only one justice may be elected in any year. Any 4 justices shall constitute a quorum for the conduct of the court's business.
2. The chief justice of the supreme court shall be elected for a term of 2 years by a majority of the justices then serving on the court. The justice so designated as chief justice may, irrevocably, decline to serve as chief justice or resign as chief justice but continue to serve as a justice of the supreme court.
3. The chief justice of the supreme court shall be the administrative head of the judicial system and shall exercise this administrative authority pursuant to procedures adopted by the supreme court. The chief justice may assign any judge of a court of record to aid in the proper disposition of judicial business in any court of record except the supreme court. [1876 J.R. 10, 1877 J.R. 1, 1877 c. 48, vote Nov. 1877; 1887 J.R. 5, 1889 J.R. 3, 1889 c. 22, vote April 1889; 1901 J.R. 8, 1903 J.R. 7, 1903 c. 10, vote April 1903; 1975 J.R. 13, 1977 J.R. 7, vote April 1977; 2013 J.R. 16, 2015 J.R. 2, vote April 2015]

Voting and Electoral Politics in the Wisconsin Supreme Court. Czarnezki. 87 MLR 323.