The minimum wage isn't earned only by people working at fast food restaurants and in service industry work - the average income for positions like nursing assistants, preschool teachers and paramedics are all under $15.

When families can afford the basics, they can reinvest in their communities, and higher wages means a broader consumer base for businesses.

Fast food also has a uniquely difficult business structure for workers to achieve better wages and working conditions.

Today, the gap between productivity and compensation for the typical worker is larger than at any time since World War II.

Most fast-food workers can't easily join a union, because they don't work directly for their parent company, such as McDonald's or Subway. Instead, they work for individual franchise owners, ensuring that each individual fast-food outlet would have to organize and win union recognition separately. So there's not one central employer to bargain with, as in a traditional union campaign.

The fast-food industry is notorious for employing millions of Americans at poverty wages.

A September 2015 poll found that, by a 3-1 margin, voters are more likely to support political candidates who favor raising the minimum wage.