In just two years, more than 13 million workers have received a raise, most notably in Los Angeles, Chicago, Seattle, Massachusetts and just last month in New York, where wages for fast-food workers were raised. 

Work strikes and broad-based mass mobilizations are inspiring and filling a much-needed void. This worker-led movement is stepping in where the federal government has failed. 

Nearly 50 percent of workers earn less than $15 an hour and 43 million are forced to work or place their job at risk when sick or faced with a critical care giving need. When Hillary Clinton, Bernie Sanders, Jim Webb, Martin O'Malley, and Lincoln Chafee take the stage in Las Vegas on Tuesday night for the first Democratic presidential debate of the 2016 election, will they be addressing this powerful and significant constituency?

Will they provide relief for working families by presenting real policy solutions that go to the core of what it means to thrive? Or will they trade sallies and barbs in a bid to prevail in a popularity contest, overshadowing the experience of millions of working families in America?

Democratic contenders are likely to lament the fate of a declining middle class squeezed by the rapacious appetites of the 1 percent. This is important, but the candidates will also need to focus on ensuring that the middle class grows through a fair minimum wage, and struggling American workers, many of whom are women and people of color, can take paid sick time off without being penalized.

Not in recent decades have we seen such a vibrant backdrop of resistance and organizing around wages and workers' rights in this country, and Democratic candidates must not squander this golden opportunity to raise awareness around these issues and set an agenda that goes to the heart of what Americans need.

And the workers have been heard: a $15 minimum wage has been passed in the nation's largest cities. In addition, laws raising the minimum wage to more than the federal standard of $7.25 an hour have passed in a number of states and cities. There are now campaigns to raise the floor and standards for workers are being led in 14 states and four cities.

We've seen how lives can change when workers are paid a salary allowing them to make ends meet. Unable to adequately provide for her family on $9 an hour, health-care worker and single mother Sandra Arzu is one of the workers who fought fora $15 minimum wage in Los Angeles. The raise will fundamentally change her life and ability to put food on the table for her family and pay the rent.

Higher wages are vital to improving the lives of low-wage workers but it's not a cure-all. It's also important for low-wage workers to have access to paid sick days to take care of themselves and their families without fear of retribution. A Center for Popular Democracy report published earlier this month reveals 40 percent of surveyed Starbucksworkers reported facing barriers to taking sick days when they were ill.

The candidates need to address in a real way what workers must manage daily. Like a Starbucks barista from Washington State who describes coming to work sick out of fear she would lose her job if she took the day off. She says she rested on cardboard spread out on the floor so she could step in when there was heavy foot traffic in the store.

The federal government has an opportunity to dignify the lives of all workers in this country and address persistent inequality by enacting nationwide policies raising the minimum wage and enforcing paid sick leave. Millions of workers have issued a clarion call to the Democratic candidates and it's now their turn to respond with aggressive policy solutions to address the divide in this country.

We will be watching closely on Tuesday night to see if the candidates have heard the call from this key Democratic constituency — a constituency the Democratic party can't afford to lose.

Source: CNBC