Michael Madigan, the former speaker of the Illinois House and for decades one of the nation’s most powerful legislators, was charged with racketeering and bribery on Wednesday, becoming the most prominent politician swept up in the latest federal investigation of entrenched government corruption in the state.Madigan, 79, is charged with 22 counts, according to the indictment.Read the full indictment.Madigan was the longest-serving state House speaker in modern U.S. history and was nicknamed the “Velvet Hammer …