A year ago, the White House and Democratic lawmakers embarked on a campaign to make the minimum wage a defining issue in the 2014 elections. And although that didn't pan out exactly as planned at the federal level, nearly half the states took action on the issue.

In his State of the Union address last January, President Obama urged members of Congress to pass bills from Sen. Tom Harkin, D-Iowa, and Rep. George Miller, D-Calif., to raise the federal minimum wage to $10.10.

"Say yes," Obama said. "Give America a raise."

Federal legislation was met with resistance. though. Republicans argued raising the minimum wage would cause an increase in prices for consumers and low-wage workers likely would face layoffs as companies grappled with the higher costs associated with hiked wages.

Some of those concerns were validated last month by a University of California, San Diego, study. For three years, researchers followed low-income workers residing in states that saw wage hikes and those that did not. The study found that minimum wage hikes had negative impacts on employment, income and income growth.