Photo: Eric Risberg / Associated Press

Mayor London Breed can hardly be blamed for wanting her brother’s release from prison, notwithstanding the gravity of a 2000 armed robbery that resulted in a woman’s death. Breed wants him to have a second chance at freedom, and she is determined to help him find housing and a job and otherwise succeed on the outside.

This is what family members do for one another.

Where Breed crossed the line was invoking her position as mayor of San Francisco in appealing to Gov. Jerry Brown to commute the sentence of her brother, Napoleon Brown, who has served less than half of the 42 years he received for his conviction of involuntary manslaughter and armed robbery.

Breed’s letter to the governor appealing for her brother’s early release featured “Mayor London Breed” in block letters at the top, and referenced her position in the text. She also has acknowledged that she spoke to the governor about whom to contact about the commutation.

It’s fair to assume that few Californians with a sibling in prison do not have a chance to give the governor a personal heads-up before applying for leniency.

The other issue of concern that has come to the fore is Breed’s role as an alibi witness. She has testified that she saw her brother asleep on her grandmother’s couch in the Western Addition about midnight on June 18, 2000. The robbery at the Johnny Rockets restaurant in the Marina occurred sometime between midnight and 12:40 a.m., according to various accounts.

While Breed’s story sounds suspicious, it is not implausible. The time frames are not precise, and it is at least conceivable that the brother could have woken up and reached the Marina before 12:40. That part of the story is likely to remain inconclusive — though questions about whether she gave false testimony may well haunt Breed in future political campaigns.

The bottom line is that the governor should assess the clemency request with the same standards he has applied to others that have reached his desk. The fact that Napoleon Brown has a sister in one of the state’s higher-profile offices should neither advantage nor disadvantage his application.

By that standard, Napoleon Brown has cause for hope.

When it comes to clemency, Jerry Brown has been the most forgiving California governor in modern times. He has issued more than 1,100 pardons on a wide variety of crimes, from drug dealing to driving while intoxicated to forgery. By comparison, Republican Gov. Arnold Schwarzenegger handed out 15 pardons. Democrat Gray Davis provided none.

To be sure, Napoleon Brown’s offense was horrific. Authorities said he pushed 25-year-old Lenties White out of the getaway car on the Golden Gate Bridge, where she was struck and killed by an oncoming vehicle.

But Brown has been willing to commute sentences in other difficult cases, including recent commutations for 20 killers serving life in prison. Consideration could include an inmate’s demonstration of rehabilitation and contrition, behavior in prison and evidence that the sentence was unjust or excessive in the context of current law.

Napoleon Brown deserves the fair hearing the governor has given to other inmates.

But to be clear: Having a sibling as mayor of San Francisco is not an extenuating circumstance.

This commentary is from The Chronicle’s editorial board. We invite you to express your views in a letter to the editor. Please submit your letter via our online form: SFChronicle.com/letters.