Even retail giant Wal-Mart Stores Inc., the nation's largest private employer, which came under fire for years from politicians and labor groups for inadequate health care benefits, is calling for universal health care. The company joined a health care reform coalition with labor groups in 2007 with the goal of providing health care to all workers by 2012. Wal-Mart covers 51.8 percent of its 1.4 million U.S. employees, in terms of health care benefits, according to a spokesman. He said 5.5 percent of Wal-Mart's workforce is uninsured, while 94.5 percent of its U.S. employee base has some type of health care insurance. The politically volatile issue is sure to test the political will of many lawmakers and will partially define Obama's presidency.