MADISON, Wis. (AP) _ One of the most moderate Republicans in the state Legislature will retire rather than take on a more conservative challenger. State Sen. Dale Schultz says he will retire after 31 years in the Legislature rather than seek re-election this fall. He is being challenged by conservative Rep. Howard Marklein, of Spring Green. Schultz did not immediately return a message seeking comment Monday. Schultz was the only Republican in the Senate to vote against Gov. Scott Walker's union law known as Act 10. He also went against Walker and Republicans on other issues, including loosening environmental laws to ease the opening of an iron ore mine in northern Wisconsin. In addition to Marklein, Democrat Ernie Wittwer is also running of the seat.