FORT LAUDERDALE, Fla. (AP) — Attorneys for Parkland, Florida, school shooter Nikolas Cruz will have one goal when jury selection starts Monday: to identify candidates who might give Cruz the single vote he needs to get a life sentence instead of death for the 2018 murders of 17 students and staff members. The process will involve a lot of educated guesses.

Court officials said perhaps 1,500 or more potential jurors could file through Circuit Judge Elizabeth Scherer’s courtroom over several weeks as she, prosecutors and Cruz’s public defenders select 12 panelists, plus eight alternates, for his penalty trial. Those chosen must say they can put aside their animosity toward Cruz for the 2018 massacre at Marjory Stoneman Douglas High School and judge the case fairly. The potential jurors must also be available through September.

Cruz’s attorneys “should not even try to get a jury or juror who doesn’t know about the case because that is ignorance; you would have to be living under a rock,” said Orlando defense attorney Mark O’Mara. O’Mara came to national prominence after his successful 2013 defense of George Zimmerman, who was acquitted of murdering Black teenager Trayvon Martin. He is not involved in the Cruz case.

Jury candidates who declare that they can be objective will complete a questionnaire that dives into their backgrounds and asks whether they can handle viewing graphic evidence. They will then return in a few weeks for courtroom interviews, where they must declare that they are able to vote for the death penalty but also don’t believe it should be mandatory for murder.

Cruz, 23, pleaded guilty in October to 17 first-degree murders, 17 attempted murders and a jail assault, leaving the jury to decide only whether the former Stoneman Douglas student gets death or life without parole.

Instead of deciding whether someone is guilty based upon objective evidence, jurors sitting at this death penalty trial must answer a subjective question: Have prosecutors shown that aggravating factors — the number of deaths, the weeks of planning and the cruelty and horror of Cruz’s actions — outweigh mitigating factors such as his lifelong mental illness and the death of his parents? For Cruz to get death, the jurors must all answer, “yes.”

To get at least one “no” vote, Cruz’s attorneys must show that his path to the murders wasn’t “pure 100% personal-created intent,” said O’Mara, who has defended about a dozen capital cases that ended with no death sentences imposed. “It is going to be difficult. … Death is the default sentence in this case.”

The fact that no one who opposes capital punishment on principle can be selected for the jury eliminates some female, minority, religious and liberal candidates who could potentially be sympathetic toward Cruz, Miami jury consultant and lawyer Geri Fischman said.

White people strongly support the death penalty, a Gallup poll last year showed, while most Black and Hispanic people oppose it. The survey also showed that more women oppose capital punishment than men, and that only a quarter of liberals support the death penalty compared with 70% of conservatives. Broward County is 2-to-1 Democratic.

Catholic Church leaders, some Protestant denominations and Judaism’s major rabbinical organizations also oppose the death penalty on theological grounds, although many individual members support it in practice.

“Death-qualified juries are skewed in favor of the prosecution,” Fischman said.

This won’t be the first time Scherer, prosecutors and Cruz’s attorneys begin picking a jury for him. In October, Cruz faced trial for assaulting a jail guard nine months after the shooting. Prosecutors wanted a conviction to use as an aggravating factor in their argument for the death penalty.

Almost 300 prospective jurors were screened, 10 times what is typical in a Florida assault case. About half said they couldn’t judge Cruz fairly, and three women cried just seeing him. The other half said they could be just, but the process ended with Cruz’s sudden guilty plea.

Until 2016, a Florida judge could impose the death penalty if a majority of jurors agreed. But after the U.S. and Florida supreme courts mandated a higher bar, the Republican-majority Legislature amended the law to require unanimity. This is the system used in 18 of the 26 other states with capital punishment.

That change gives Cruz a chance, but the jury’s composition is key, O’Mara and Fischman note.

Both prosecutors and defense attorneys can strike a potential juror if they are able to persuade Scherer that the person’s background or answers demonstrates unfairness. Cruz’s attorneys might challenge school employees, for example, or someone with a relative who died at the hands of another.

Both sides receive 10 peremptory strikes for any reason except race or gender. Scherer has indicated she might add more, given the case’s high profile.

Fischman said that if she were advising the defense, she wouldn’t preclude any occupations, ages or economic groups. Instead, she said she would look closely for “stealth jurors”: candidates who skew answers to be picked so they can vote for death.

“Anyone who tells you repeatedly they are going to be fair, that they have no biases, that they have no preexisting views on this case, is likely hiding something,” she said. “Someone who says they have no views on a shooting where innocent children were killed is not being … forthright.”

O’Mara said he might seek racial minorities and jurors with relatives who have been criminal defendants because they might be “more sensitized to the inconsistencies and biases of the judicial system.”

He said he would avoid accountants, engineers and others whose occupations require “very precise” answers. Such professionals use a mental scale to precisely weigh the aggravating and mitigating factors — a battle Cruz cannot win with 17 dead victims, he said.

“When you get to that kind of analysis, you get away from what the defense wants: the humanity” of the jurors and the defendant, he said.

The bottom line: A case like Cruz’s has no certainties for the defense.

“You are, in effect, playing to one juror — you just don’t know which,” O’Mara said.