As many legislatures around the country have finished their work for the year, fewer than one-fourth of states have taken concrete steps to create health insurance marketplaces, a central feature of the federal law to overhaul the U.S. healthcare system. A total of 43 states, meanwhile, have made fresh cuts to Medicaid, even as lingering unemployment and diminishing access to private coverage continue to drive up the number of Americans turning to the public insurance program for the poor. Taken together, these trends highlight the ground-level challenges that health care poses to states. A year after Congress passed the biggest revisions to the health-care system since the 1960s, states are grappling with their own versions of the fiscal and ideological battles that still are roiling Washington. States that have moved gingerly so far on health exchanges have not necessarily rejected the idea outright. Only one, Louisiana, has told the federal government it does not intend to build an insurance marketplace for its residents. In states that refuse, the law allows the federal government to step in.