(Photo: AP/Mike Groll) A man listens to a speaker during a rally to raise the minimum wage outside a McDonald's restaurant at the Empire State Plaza concourse in Albany, N.Y in May 2014. O n July 24, 2009 the federal minimum wage was increased from $6.55 to $7.25 an hour, the third and final increment of a bipartisan-backed law passed in 2007. In the eight years since, the United States’ wage floor has remained stuck at that level, the prospects of an increase stymied by congressional inaction and hostile corporate influence. For decades, the federal minimum wage was a rather effective tool for ensuring that workers could earn enough to support a family. Now, its power has been all but eroded. At the minimum’s peak value in 1968, a full-time minimum-wage worker earned about $19,500 in today’s dollars, enough to keep a family of three above the poverty line. Through the early 1980s, the minimum wage remained strong enough to keep a family of two out of poverty. Since then, the minimum...