The United States has struggled with how to adequately provide health care for its poor and middle class for a long time. The Affordable Care Act (ACA) seeks to lessen that struggle but clearly does not resolve it. When Medicare and Medicaid were passed in 1965, many clearly also believed that the struggle would be relieved or eventually resolved. Fifty years later it is clear that Medicare has not played that role. Surprisingly, Medicaid, our means-tested target program for America's poor, elderly, and disabled, has been much more expansionary over the years. Articles in this special themed issue, "America's Struggle with Medicaid," examine the contradictions and struggles of this divisive program.