SIOUX FALLS, S.D. (AP) — South Dakota voters on Tuesday are weighing whether to expand Medicaid health insurance to tens of thousands of low-income residents through a constitutional amendment. If Constitutional Amendment D is approved by a majority vote, it would remove South Dakota from a list of 12 states that have not expanded eligibility for the government health insurance program to people earning up to 138% of the federal poverty level — currently about $18,800 for an individual or $38,300 for a family of four.