Still wondering how Donald Trump managed to win over working-class voters by promising to bring back manufacturing jobs? Take a look at “Sweat,” Lynn Nottage’s timely, empathetic and critical-minded drama about how the shutdown of a factory in Reading, Pennsylvania, leads to the breakdown of friendship and family, and a devastating cycle of violence, prejudice, poverty and drugs.

“Sweat” opened Off-Broadway at the Public Theater just a few days before the presidential election. After Trump’s unexpected win, it has taken on a bruising urgency that more than justifies transferring it to Broadway.

The play begins in 2008, with two young men struggling to adjust back into society after long prison sentences. Wondering how their lives went astray, we flash back to 2000, when they are working at a local factory alongside their mothers. Over time, the factory starts to downsize and demand substantial pay cuts, leading to strikes, lockouts and the hiring of nonunion workers.

The characters don’t necessarily love doing manual labor on an assembly line (in fact, they complain of body pain and a lack of respect from upper management). But for them, it is steady work with a decent wage. Some are from families that have worked for the same company for generations. Losing their jobs threatens their identities too.

“Sweat” is an involving drama, calibrated to increase in intensity toward its brutal climax. Nottage, who won a Pulitzer for “Ruined,” explores her characters and their environment with the sensitivity of a master dramatist and the objectivity of a journalist. She doesn’t provide any answers, only the faintest hope that people will take care of each other, even in desperate circumstances.

In terms of performances, Kate Whoriskey’s finely textured production is a triumph of ensemble acting. Johanna Day is particularly effective in expressing her character’s shock, frustration and self-centered ego.