Middleton police are refusing to release the drunk driving arrest report for Democratic State Senator Russ Decker of Schofield in Marathon County. Parts of his senate district include Rusk, Taylor and Sawyer counties.
Decker has apologized for his arrest, which occurred after he left an all-you-can drink party held by tavern lobbyists in Madison late Tuesday.
Government watchdogs say police are taking advantage of a state Supreme Court decision in 1991 that exempts police reports from the state's open records law.
Governor Jim Doyle last month called for the law to be changed, saying the exemption is too sweeping.
The exemption was also used to seal the records of the arrest of Democratic State Representative Frank Boyle of Superior for drunk driving in December.