MADISON, Wis. — The state Supreme Court is weighing several key questions related to Wisconsin’s political John Doe investigation, including whether the stalled probe will be allowed to resume. But testimony is now being taken in another John Doe-related lawsuit that could further shine light on the abuses perpetrated by the prosecutors and their partners at the state Government Accountability Board. In December, following the release of bombshell documents that exposed the GAB as a rogue agency fixated on its “parallel” probe into Wisconsin conservatives and the campaign of Gov. Scott Walker, the attorney for plaintiffs in the lawsuit against...