According to the Sept 25, 2006 issue of Newsweek, a concept called "parental alienation" is now "the leading defense for parents accused of abuse in custody cases, according to domestic violence advocates. Conceived in the 1980s, parental alienation proposes that children fear or reject one parent because they've been corrupted by the other.
While it's commonly known that batterers use children to further abuse their partners, this tool give more teeth to the threat. It works in part because various parts of the judicial system do not communicate with each other, or judges decide that evidence of spousal abuse is irrelevant to custody cases. Or because there is little documented evidence--because if there was a report of spousal abuse, oftimes the abused spouse is further abused by the justice system when Child Protective Services take children away for failure to protect them from an abuser even though the abused partner took steps by reporting abuse.
The Newsweek article suggests that this tide may be slowly turning, as a few states begin to limit the use of parental alienation in cases involving domestic violence, and as the abused and their attorneys connect with each other across the country and craft legislation intended to tease out abuse of the law from real cases of parental alienation.