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

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.

When workers make more money, they respond by being more productive in their jobs and are less likely to leave, reducing turnover costs. This puts money in business' pockets, and workers also then have more money to spend in the local economy.

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.

Annual earnings in the fast-food industry are well below the income needed for self-sufficiency, and fast-food industry jobs are also much less likely than other jobs to provide health benefits.

The vast majority (over 80 percent) of fast-food and similar low wage service jobs (<$9.24/hr) are held by adults. A quarter are adults over 40. Another quarter are moms raising kids.

The free market hasn't done a very good job "figuring out" how to pay workers enough. If it was solely up to the market, the people with the least power would be paid pennies ... or less.