SPRINGFIELD — The state’s most powerful politician once explained that while mulling a tough decision, he’d often glance across his desk at a photo of the late Chicago Mayor Richard J. Daley “and just ask myself, ‘What would he do?’ It’s very helpful.”Michael Madigan’s fealty to the man both lauded and lambasted as “the Boss,” who died nearly a half-century ago, is understandable. Madigan, who made a hobby of collecting and consolidating power in nearly four decades as speaker of the Illinois House, owed his career to …