A woman could be the staunchest opponent of the death penalty, but if someone kills her child, that woman could easily murder the culprit.

And few juries would convict.

As the mother of grown children, Mare Winningham intuitively understood her character, Patrice Kelly, who was put in such a grim situation. In the Tuesday, Oct. 23, episode of ABC's "Boston Legal," Kelly seeks the advice of Alan Shore (James Spader) on how to kill the man who killed her daughter.

The following week, Shore needs to defend her.

"She is a woman determined to get away with murder, and she does have a very powerful motive to do so," Winningham says while making tea at her Los Angeles home.

"It's a great role and colorful, and I never played a Boston blue blood before," she says. "Upscale, up-do, beautiful clothes, pearls, very Jackie O. And it was really interesting to be in scenes where I know David E. Kelley was giving James Spader a moral conundrum."

Shore is such a cocky character that it will be interesting to watch him grapple with situational ethics.

Spader, who just won his third Emmy for playing Shore, says he does not even try to describe his character. He was, however, far more effusive when it came to chatting about Winningham, with whom he never before worked.

"She is a wonderful actress and a lovely person," Spader says, "and you could not find someone easier to work with in terms of being so exceptionally prepared and yet flexible when you are working through a scene and where to go. She is absolutely lovely to work with -- thoughtful and smart and funny and patient."

Patrice is such a quirky character, Spader and executive producer Bill D'Elia say, that she needed a very select actress to bring her to life.

D'Elia, who worked with Winningham on Kelley's short-lived "The Brotherhood of Poland, New Hampshire" likens her approach to Spader's.

"They are so truthful in their commitment to the role," D'Elia says. "The truth of character that comes through when Mare is working on something. And she is such a collaborator that you know you have someone who will try different things and brings so much to the party."

D'Elia is coy about whether Patrice could be a recurring character. "Once we set somebody in the orbit of 'Boston Legal,' that person always exists," he says.

Though the two episodes were unavailable at press time, the plot sounds like a situation to which any parent could relate.

"I can imagine that most parents would certainly have empathy for a woman in that set of circumstances and might have understanding for her impulses," Spader says. "Whether they would carry things out in the same way she does, I would doubt that."

"We have something that none of us can relate to -- killing someone -- but if somebody touched one of my kids, uh-oh," Winningham says.

She openly discusses anything -- from her art to religion -- except her children. Now 48 and twice divorced, she converted to Judaism a few years ago.

"I thought I was an atheist," she says. "Wow! I was really feeling strongly, completely irreligious, to come from that complete bottom, going to school and studying Judaism was very refreshing. It's a very earthbound religion, and our behavior here and how we treat one another -- it grabbed me in the best way, and then I was just in the beginning stages of building a relationship with God. It seemed like it would never happen to me, and it was a slow and good year of awakening ... I feel really lucky that I found something in life."

A longtime folk singer and guitar player, Winningham has made three CDs. She's taken up Jewish folk music and wants to write bluegrass gospel Jewish songs, which is not as strange as it sounds, as folk and gospel-influenced Jewish music exists.

For 30 years, however, acting has been her main passion. She turned professional right after high school and was the rarest of ingenues -- discovered in a high-school musical. She was Maria to Kevin Spacey's Capt. von Trapp in "The Sound of Music."

Reflecting on the school production, Winningham says, "I think it was pretty clear that we were pretty serious," she says. "It wasn't that either of us were particular lookers. We definitely had something going. We were living in the valley; it might as well have been in Iowa.

"It wasn't as if we had some inside track," she continues. "None of us were in the business. We weren't going to take head shots and get noticed. Some people talked about the play and sent some agents out, and I got an agent that way."

An original member of the "brat pack," Winningham was in 1985's "St. Elmo's Fire" and has racked up 74 credits in 31 years.

"I always thought of the other route, of going to Juilliard," she says. "I always regretted not pursuing my studies -- up to a point. When I was 30, I realized there is a different path for each person and mine really was right for me."