There's usually one film that tops lists whenever powerful legal thrillers are debated — “To Kill a Mockingbird," set in the 1930s. Now comes a film showing how little has changed since then, based on a murder in the same Alabama town where Harper Lee wrote her masterpiece.

“ Just Mercy ” is the real story of civil rights attorney Bryan Stevenson and his fight to keep an innocent black man from being executed. It is urgent, searing and powerful, led by a first-rate cast. Though it portrays events more than 25 years ago, it is very much a film of 2019.

Michael B. Jordan portrays Stevenson, who founded the Equal Justice Initiative, a legal organization that has successfully challenged the death row convictions of more than 130 inmates. Earlier this year, he was the subject of HBO's film “True Justice: Bryan Stevenson's Fight for Equality.”

Stevenson has been a dogged fighter for justice, someone Archbishop Desmond Tutu once called “America’s Mandela.” When Starbucks was faced with a racially charged uproar over the arrest of two black men at one of its stores in Philadelphia, it turned to Stevenson for advice.

The film follows one of his first cases, that of Walter McMillian, a black pulpwood worker sentenced to death for the 1986 fatal shooting of an 18-year-old white woman. Stevenson was able to prove that a key witness had lied and prosecutors withheld important evidence.

McMillian is played by Jamie Foxx and it is his best work in years, raw, soulful and honest. Tim Blake Nelson, as the key witness, also turns in a stunning performance, as does Rob Morgan playing a death row inmate. Brie Larson as Stevenson's assistant is unflashy and strong. Jordan is the calm, quiet anchor of the film, his kind eyes radiating pathos.

In a pivotal scene, Foxx's character asks Stevenson why a Harvard-trained attorney has come down to the South and risked violence to do this legal work. “I know what it's like to be the shadows," Stevenson responds. “That's why I'm doing this.”

Destin Daniel Cretton directed the film from a screenplay he co-wrote with Andrew Lanham, based on Stevenson’s bestselling 2014 memoir. Stevenson is also an executive producer, and that ensures he's illuminated in the best light.

So if there's one weakness in the film, it's that it sometimes veers into hagiography. The naturalism of the cinematography and acting sometimes clashes with dialogue that seems overly polished.

"I just want to help people," Jordan says at one point. “I just have to figure out how.” In another scene, Foxx declares to his attorney: "I got my truth back. You gave that to me."

The film at times follows other great courtroom dramas that build to a emotional conclusion such as “My Cousin Vinny” and "A Few Good Men" but “Just Mercy” has larger and deeper social issues constantly swirling, including criminal justice reform, the death penalty and racial profiling. If ever there was an example of how film can slide from entertainment to advocacy, this is it.

With the exception of Larson and a young corrections officer, no white characters come across as anything but venal and Alabama is portrayed as a place where African Americans are “guilty the moment you're born.” While it ends on a happy note, you cry for all those generations of people railroaded into a cell. “Just Mercy” is not always an easy film to watch, but it is necessary.