In Minnesota, the state House and Senate have each passed bills to raise the minimum wage and plan to iron out their differences early next year after failing to approve similar measures the past two decades.
"You're coming out of a deep recession, and people are landing jobs, but they're low-paid," says state Rep. Ryan Winkler, sponsor of the House bill.
The legislative movement has been partly fueled by walkouts this year in at least 100 cities by fast-food workers who are calling for $15-an-hour pay and the right to form unions. Wal-Mart workers have staged similar protests.
While the demonstrations were not explicitly intended to prompt minimum pay increases, they've made the issue" more urgent," Temple says.
(Counterpoint: The real facts about inequality)
The Bureau of Labor Statistics estimates that 3.6 million hourly paid workers received wages at or below the federal minimum in 2012—almost 5 percent of all employees on hourly pay schedules.
President Obama recently said he supports legislation in Congress that would lift the federal minimum wage to $10.10 an hour in three steps over two years and then index it to inflation. But the measure faces an uphill climb in Congress.
(Read more: Minimum wage: Democrats' 2014 strategy?)
Proponents of minimum-wage hikes note that low-wage jobs have dominated payroll growth in the 4-year-old recovery, and increases over the past four decades have not kept pace with inflation.
Opponents say the increases raise employer expenses and will lead to layoffs. "If your costs are going up and you can't raise prices, you have to find a way to produce the same product at a lower cost," says Michael Saltsman, a research fellow at the Employment Policies Institute.
(Read more: Middle class barely hanging on)