Tasha Kenney woke up at 4 a.m. on Thursday, donned a pink T-shirt and drove to the courthouse in Plymouth, Mass., to show support for Lindsay Clancy, the mother on trial for killing her three young children. Ms. Kenney, a teacher who lives 90 minutes away, joined hundreds of other pink-clothed women gathered on the courthouse lawn because she had suffered from severe postpartum depression after the birth of her daughter a decade ago. And she believes the Clancy children could have been saved if the warning signs had been heeded.

As Americans have been riveted by the televised trial of a woman accused of the most incomprehensible of crimes, the Clancy family's tragedy has also become a case in point for all manner of perceived societal ills. For many, it is evidence that the United States neglects new mothers and fails to properly care for maternal mental health. Others are outraged that the methodical killing of three innocents could be treated as anything other than murder. They see the nearly $1 million that has been donated to a fund for Ms. Clancy's parents as evidence of "cultural rot."

Jonathan Hatami, a child abuse prosecutor in Los Angeles County, said in an interview that he was disturbed that people seemed more worried about Ms. Clancy than the children — ages 5, 3 and 8 months — that she has admitted to having killed. While there are important issues that need attention, he said, "We can't be killing children and then say, 'Oh, I'm happy now that mental health is being discussed.'"

Twenty-five years ago, the country was equally riveted by a strikingly similar case. Andrea Yates, who like Ms. Clancy was a nurse, drowned her five children in the bathtub. Like Ms. Clancy's defense, Ms. Yates's centered on the claim that she was suffering from profound psychosis. The jury found her guilty, but she was granted a new trial. The second jury acquitted her by reason of insanity. Since then, mental illness has become less stigmatized, legal experts say, but the question of whether it diminishes culpability remains a subject of heated debate.