Edmund G. (Pat) Brown was governor of California from 1959 through 1966 (he died in 1996).
During his time as governor, he commuted 23 death sentences (more than any California governor before or since), and had 36 people "executed".
His book Public Justice, Private Mercy, subtitled A Governor's Education on Death Row, was published in 1989. The following is its concluding paragraph.
"I am eighty-three years old as I write these words. I've done many things during my life that have given me a great deal of pleasure and pride, and a few things that I'd either like to forget or to have another chance at. But the longer I live, the larger loom those fifty-nine decisions about justice and mercy that I had to make as governor. They didn't make me feel godlike then: far from it, I felt just the opposite. It was an awesome, ultimate power over the lives of others that no person or government should have, or crave. And looking back over their names and files now, despite the horrible crimes and the catalog of human weaknesses they comprise, I realize that each decision took something out of me that nothing -- not family or work or hope for the future -- has ever been able to replace."