Chicago's recent "big-box" ordinance is representative of a larger labor movement: stymied at the federal level, proponents of a higher minimum wage have found more success with states and cities. Some 20 states have minimum wages higher than the federally mandate standards, with six more considering putting such measures up for referendum; Chicago's ruling mirrors those of cities like Los Angeles, Washington, DC, and Madison, WI, and may inspire similar movements elsewhere.
See "Activists dig in on smaller scale", Barbara Rose, Chicago Tribune, July 27, 2006