Wisconsin taxpayers are funding a $850,000 legal contract to defend GOP-drawn legislative district maps, but they don’t know what it says.

Republican Assembly Speaker Robin Vos told the Milwaukee Journal Sentinel this week that he won’t release the contact drawn up with Bartlit Beck, the Chicago-based firm the GOP-controlled assembly hired to help them with this work.

Vos’ spokesperson told the newspaper that the document was covered by attorney-client privilege. But transparency advocates countered that Vos’ decision violates Wisconsin’s open records law, and noted that the assembly has publicly released contracts with other firms handling redistricting work.

The maps at issue have allowed Republicans to control both houses of the state legislature since the lines were drawn in 2011. They were ruled unconstitutional by a panel of federal judges in 2015 because they were so favorable to the GOP, but the Supreme Court declined last June to take up the case.

Democrats who brought the suit have since added new plaintiffs, and a new trial before the panel is slated for April. Newly elected Democratic Attorney General Josh Kaul has pledged to defend the Republican-drawn maps on behalf of the state.