Las Vegas — MARYLAND PARKWAY, a street in central Las Vegas best known for its gritty shopping centers and petty crime, is now home to a brightly lit campaign office. Cartoon portraits of an aging senator with oversize glasses and wild cowlicks hang around the main room. On the wall is a growing collage of handwritten signs explaining “Why I’m voting for Bernie”: because “Minimum wage is not enough,” because “College should not be a financial obstacle,” because “I am a socialist.”

Bernie Sanders was never expected to get as far as the Nevada caucuses, which take place Feb. 20, let alone do well in this blue-collar, conservative state. And yet, in recent months, and especially in the wake of his blowout win in the New Hampshire primary, there is a sense that the old verities are falling apart and that the avuncular, bespectacled Vermonter could win over a sizable chunk of the union members and minority voters who were supposed to vote in lock step for Hillary Clinton.

It’s not purely coincidence: Even as he stumped in Iowa and New Hampshire, Mr. Sanders didn’t ignore Nevada. The office on Maryland Parkway is one of 11 spread around the state (Mrs. Clinton has seven). He has spoken to overflowing crowds in Las Vegas and Reno. Like those handwritten signs, the speeches took on the same laser-focused economic theme that, increasingly, many working-class Nevadans appear receptive to.

That’s because, while Mr. Sanders’s message of taking up policy arms against the billionaire class may sound like so much heated campaign rhetoric, in Nevada — which was not only the state hardest hit by the recession and housing crisis but also has been the slowest to recover — it speaks to unfinished business. The state has some of the highest rates of unemployment and child poverty in the country. In our glacially recovering housing market, one out of four homeowners still has negative equity in their homes.