Because there was no dispute that Mary shot Matthew, the jury was faced with deciding first whether it believed Mary and, if so, whether the physical, verbal and sexual abuse excused her husband's murder.
At least one commentator believes that the abuse isn't enough. "It's just not justifiable to voluntarily marry someone and then kill him just because he was not a good person," said former federal prosecutor and University of Southern California law professor Jean Rosenbluth. "There must be self-defense or imminent harm to you or someone else to have a right to repel that threat."
The jurors — some of whom believe Mary committed first degree murder and others who think she should have been acquitted — compromised and ultimately found her guilty, not of being a cold-blooded killer but rather a woman provoked after years and years of abuse.
In legal terms, she was convicted of voluntary manslaughter, and instead of facing life behind bars she now faces at most three years to six years in prison with the possibility of probation. Many debate whether or not this is enough jail time because Mary killed her husband in his sleep.
"Three [years] to six years is a blip in her life and his is gone forever," Rosenbluth said.
Criminal defense lawyer Mark Geragos says he thinks the range is fair given the extenuating circumstances.
"The abuse, coupled with the mother's instinct to protect her children, is sufficient justification to impose a less severe sentence," Geragos said.
Lenore Walker, a psychologist who interviewed hundreds of victims of domestic abuse, first coined the term battered woman syndrome in the late 1970s. Since then the courts have begun to accept this growing body of research and have recognized that battered women who commit certain crimes may have various legal defenses available to them because of their dire circumstances.
Despite the research, however, expert testimony regarding battered woman syndrome is specifically recognized in only 12 states, and is not on the books in Tennessee.
Mary's attorneys had to argue that she suffered from post-traumatic stress disorder, a condition many Vietnam veterans suffered from, in order to convince the jury that Mary's abusive situation rendered her unable to form the intent to commit first degree murder Despite battered woman syndrome's well-documented history, it has been an uphill battle to convince juries that such domestic abuse is a justifiable defense to murder -- until now.
Today, at Mary's sentencing hearing, we will learn what the judge thinks of this syndrome and whether or not Mary will be going to jail.