“It’s got to be really confusing for the average citizen who sees both things going on and doesn’t understand how all of the above can be occurring,” said Michele Hanisee, the president of the Association of Deputy District Attorneys in Los Angeles County. She is seeking a death sentence in one of her cases: the man accused of being a serial killer, Alexander Hernandez, who is charged with killing five people in a shooting rampage in the San Fernando Valley in 2014.

“The simple answer is this: The district attorneys of the state of California took an oath to uphold and follow the law,” Ms. Hanisee said. “I think the governor probably did too, but he doesn’t care.” The governor, she added, does “not have the legal authority to tell them not to seek death or not to follow the law.”

New death sentences in California have declined in recent years; 2018 was a record low, with five new sentences. The drop aligns with a national trend, as public support for capital punishment has waned and juries have been reluctant to impose death sentences in the face of evidence of racial disparities and high-profile exonerations. Before Mr. Newsom’s moratorium, 20 other states, including most recently Washington and Delaware, had abolished the practice.

Public support for capital punishment across the country has dropped substantially since the 1990s, according to polling data from Gallup.

California, while maintaining a large death row, has not executed anyone since 2006. There were longstanding legal challenges to the state’s lethal injection protocol that had halted executions even before Mr. Newsom’s moratorium.

Many supporters of capital punishment say that while the system can be reformed to reduce racial disparities, and thus produce fewer death sentences, the penalty should remain an option for prosecutors and juries in the most heinous of crimes, including some of the cases underway in California.