MADISON, Wis. (AP) – Gov. Scott Walker says he still hasn’t decided whether Wisconsin will seek a voluntary expansion of Medicaid services as provided under the federal health care overhaul.  Walker made the comment in a Monday interview with The Associated Press.        Walker earlier this month said Wisconsin would not move forward with implementing its own state-run health insurance exchange under the Affordable Care Act. But Walker has not said whether Wisconsin will expand Medicaid services under the law, which he and other critics have called “Obamacare.”  The expansion is set to take effect in 2014 unless states opt out.  Walker has been critical of the expansion in the past, raising concerns about how much it would cost the state.