At some moments in our history, this sort of upward mobility has proved elusive. But when the United States has enjoyed booming new industries that offer good-paying jobs to large numbers of people, effective institutions of training and assimilation, and a strong communal spirit of aid and shared purpose, such opportunities have been broadly shared.

Oren Cass: Economic piety is a crisis for workers

Today, though, outside of a few concentrated pockets of high growth in digital technology, American industrial innovation has slowed and workers in once-populous industrial regions have lost stable employment. For increasing numbers of Americans, enrolling at a four-year college is more likely to lead to debt and ambiguity than to a clear and productive career. Local organizations that once provided workers with a sense of representation and community, such as unions, have seen their memberships and budgets decline into near-oblivion.

To feel the absence of the American dream, and to desire to re-create an America in which it exists, is to experience nostalgia, but of a particular kind. It is not necessarily a desire for the old things, for low-tech assembly lines, male-only colleges, or debilitating labor disputes. It is a desire for an old promise, that no matter what America looks like or how it has changed, a stable and prosperous life should be attainable for the many. It’s an undying spirit that defines and unites us as Americans.

I’m proud that my mother and father could provide, through their hard work and commitment to our family, the opportunity for me and my siblings to flourish. They came to America in a time of prosperity, when working-class immigrants could assimilate and thrive alongside Americans whose families had been here for generations.

When I was born, in the early 1970s, the median income for families like mine, with a few kids and parents with only high-school degrees, was nearly two and a half times the poverty line. Today it’s less than one parent’s paycheck away from the poverty line. Simply put, if my family faced the exact same circumstances today, we would not be middle class; we would be falling behind. And if hardworking Americans don’t have stable jobs that pay enough to buy a home and raise a family, our nation is in very serious trouble.

Caitlin Zaloom: Does the U.S. still have a “middle class”?

Many policy makers in Washington and commentators in New York realize that the 21st-century economy is causing deep disruptions to Americans’ work lives, and that something new must be done to help them succeed. The debate over the “future of work,” though, is too often concerned with what workers need to do in order to become more useful to businesses, placing the responsibility of adjusting to automation and outsourcing by pursuing job retraining on workers themselves. In the process, the discussion absolves government and business of any responsibility for creating an economy that exists to benefit working Americans.