MADISON, Wis. (AP) – The state Senate is debating a bill designed to weaken the Milwaukee County Board.  The Republican-controlled Assembly passed the measure last week and the Senate took it up Tuesday.   Democrats have opposed the proposal as an attack on local control they say could spread to other local governments around the state.  But Republican backers say they are solely focused on problems they see with the Milwaukee County Board.  The bill would reduce the Milwaukee County Board’s resources and authority, increase the power of the county executive, reduce the terms of county supervisors from four to two years, and require a binding referendum next year on cutting supervisor salaries in half.