Setting up more conflict with the Republican-led legislature, new North Carolina Democratic Gov. Roy Cooper on Wednesday announced plans to expand Medicaid through the federal health care overhaul, even though a state law specially prevents such unilateral action. Cooper, the attorney general for the past 16 years before narrowly beating GOP Gov. Pat McCrory in November, announced at a New-Year economic forum that he plans to file paperwork with federal regulators by Friday. Cooper’s action comes in the waning days of the administration of President Barack Obama, who championed the 2010 health care law and wants to protect his legacy,...