My ex-boss, Special Counsel Robert Swan Mueller III, may soon be fired by the president. Let me tell you about him.

We first met in August 1998, when he became United States Attorney in San Francisco. U.S. Attorneys enforce federal law in their districts. I was one of several dozen assistant U.S. attorneys.

Little in Mueller’s background appealed to me. His high school was the St. Paul’s, famed New Hampshire boarding school. Mine was Box Elder High School in Brigham City, Utah. He was a Princeton man. I was U. of U. My first job was dishwasher on the graveyard shift at Jesse’s Cafe in Perry, Utah. I didn’t know what Mueller did on his first job, but I was willing to put money down that it had nothing to do with dishwashing or graveyard shifts.

One thing stood out in his biography. He joined the Marines in 1968 and received a commission as a second lieutenant. If you wanted a ticket to Vietnam in 1968, becoming a Marine second lieutenant was a surefire way to get one. There were four reasons for making such a choice. First, you believed it was your duty to serve your country. Second, you thought service in combat benefited a political career. Third, you sought to test your manhood. Fourth, you believed that American involvement would result in victory. I prayed that his reason was the first. The second and third reasons were not worth dying for. The fourth reason — by 1968 — suggested a deficit in clear thinking. Mueller and I did have one thing in common: being born in 1944 during World War II.

I did not warm to him. There were many talented locals. Who needed this Easterner from Main Justice? And, to boot, he was a Republican sent by a Democratic administration to the most liberal district in the country!

But Mueller soon showed who ran things. He had a daily routine. Arriving early, he walked past each office without comment and followed the same routine at end of day. We nicknamed them Mueller’s “bed checks.” After his appointment, Bob (as we called him) called a criminal division meeting. In a civil but “I’m the boss and you’re not” tone, he spoke of his expectations. What we had been doing had not been good enough. If assistants disagreed with his approach, he suggested private practice where we “could make two or three times more money.”

He demanded excellence. Bob wanted his assistants to be the best — even at a personal price. A criminal jury trial flows into a lawyer’s every waking moment. It exacts an emotional and physical toll, especially in high-profile cases. Just ask Marcia Clark or Chris Darden what the O.J. Simpson case did to their lives. Some assistants become gun-shy, finding trials either too stressful or just too much work. Under Mueller, such folks found new enthusiasm, or they departed.

After several weeks passed, Mueller sacked all the section chiefs but one. Bob also dived into details on big cases. Before approving a grand jury indictment, he might scrutinize the entire investigative case file. He jumped on substandard performance. I had a jury trial conviction reversed on appeal. My hastily done appellate brief had been sloppy. Bob sent me to a refresher writing course. Some weeks later I referred to a recently written memorandum. “Could you send me a copy?” he asked. Just checking. …

Bob ducked media spotlights, limiting his exposure to essentials. He stopped assistants’ free-lancing with reporters. Before Mueller, the office leaked. Bob ordered all press contacts funneled through his press person. I’m not sure how he enforced this edict, but the leaks dried up. The office often had ongoing sensitive cases involving public figures. However, whether the target was a Democrat or Republican mattered little. The office was generally nonpartisan in just about everything: hiring, prosecutions and culture. I knew my close friends’ party affiliations, but I could not tell you which party most assistants favored — although we were all on a first-name basis. Party affiliation was a low office priority. Although a Republican, he’d hire a talented Democrat over a mediocre Republican every time.

Mueller vigorously guarded the office’s ethical reputation. Assistants sailing too close to the line between zealous advocacy and prosecutorial misconduct found themselves in less problematic assignments. When an assistant I knew allegedly got caught in an ethically indefensible situation, Bob called him into the office. I never saw the assistant on the job again.

Almost three years into the Mueller era, we were all working harder than ever, most experiencing Mueller fatigue. But the office was a sharper instrument. Trials had tripled. Filed cases had increased by one-third. Mueller left his stamp on everything from the office’s enhanced reputation to the size and type of font on office stationery. Then he departed to be FBI director.

Over time, my opinion of Bob underwent serious revision. In the mid-2000s, a flinty Republican friend remembering my first impression of Mueller asked with a sly smile my present opinion. I handed my friend the admission he sought. “The best, simply the best,” I replied.

When he retired from the FBI after 12 years of unparalleled service, I thought: Goodbye, Bob. But destiny, as the cliché goes, took a hand. As need for an independent prosecutor became glaringly apparent in the Jeff Sessions-led Justice Department, why was there such little speculation about Mueller? Bob should not only be among the top candidates, he should be the candidate. Suddenly, like an Atlantic squall, came Mueller’s special counsel appointment.

Donald Trump and his fellow travelers have been coming hard at Bob for months. Now it may turn really nasty. But keep in mind, I am ready to undersign this writing under penalty of perjury. Those other guys are surely not ready to do the same with their offerings.

Lawrence J. Leigh