Documentary makes the case for work of public defenders

In the court of public opinion, few get a worse rap than public defenders. Stereotyped as mediocre lawyers who sleep through trials, they are more often maligned than appreciated for protecting the rights of the indigent.

Filmmakers Pamela Yates and Peter Kinoy try to set the record straight in “Presumed Guilty,” a persuasive two-hour documentary airing tonight at 9 on KCET. The show follows four cases handled by the San Francisco Public Defender’s Office, helping us understand why these pros fight the good fight, even if it’s usually on behalf of people who have done bad things. As one defender says, a vigorous defense is like a muscle that must be exercised, lest it atrophy when needed most for the innocent client.

Two cases are misdemeanors assigned to feisty rookies; intertwined with those stories are murder cases handled by longtime defenders.

Jeff Adachi, who was motivated to study law after his parents and grandparents were interned for being Japanese Americans, defends a Cambodian immigrant accused of slaying a gang boss.

Will Maas, a Vietnam vet fighting his own demons as well as the prosecution, comes off as twisted but cunning in his defense of the alleged triggerman in a murder for hire. Maas, who tapes a bizarre video diary in the wee hours and wears big glasses in court to “peer into the souls” of witnesses, recalls a 1966 firefight to psych himself up for legal battle. A lone enemy soldier killed 12 men in Maas’ squad that day.

The lesson? “You never know,” Maas says. “You might win a battle here and there, and you might win the war.”