Mr. Carrillo’s and Mr. Williams’s meager salaries also underscore the straightforward choice we face as a nation: either we build an economy in which most workers can earn enough to adequately support their families or we build a government with the wherewithal to subsidize the existence of a lower class that can’t survive on its own. We are doing neither.

More than two million workers toil in food preparation jobs at limited-service restaurants like McDonald’s, according to government statistics. They are the lowest-paid workers in the country, government figures show, typically earning $8.69 an hour. A study by the Economic Policy Institute, a liberal-leaning research organization, concluded that almost three-quarters of them live in poverty. And they are unlikely to have ever contemplated joining a union.

On a full-time schedule, they could make a little over $18,000 a year, just about enough to keep a family of two parents and one child at the threshold of poverty. But full-time work is hard to come by. With fast-food restaurants increasingly using scheduling software to adjust staffing levels, workers can no longer count on a steady stream of work. Their hours can be cut sharply from one week to the next based on the business outlook or even the weather.

Orley Ashenfelter, a labor economist at Princeton, published a study earlier this year that captured the plight of workers under the Golden Arches in a novel way: measuring pay by the burgers a worker could buy for an hour of work, he calculated that the real wages of McDonald’s workers in the United States hit about 2.2 Big Macs an hour last year. That’s 15 percent less than in 2000.

Many economists will argue that concern about the lowly McJob is misplaced. These jobs offer a wage to people with no training or education. Mr. Carrillo, for instance, doesn’t speak English. “To get a better job at my age, you need a profession,” he says. To improve the lives of American workers, most economists argue, we might do better by focusing on education to equip them with the skills to perform more productive, better-paid jobs.