"I agree with the Court that intentionally or knowingly causing bodily injury to a family member 'has, as an element, the use . . . of physical force,'  and thus constitutes a 'misdemeanor crime of domestic violence,'" Scalia wrote, adding, "I write separately, however, because I reach that conclusion on narrower grounds." His argument has to do with previous court decision pertaining to the difference between physical force and violent force. As Irin Carmon noticed, his argument, essentially, is that the Castleman decision written by Justice Sonia Sotomayor is overly broad and relies on definitions of domestic violence from advocacy groups, specifically a amicus brief from the National Network to End Domestic Violence. Scalia cites several dictionary definitions to make his point, arguing that they define the term "domestic violence as "ordinary violence that occurs in a domestic context." He adds:  
The offerings of the Department of Justice’s Office on Violence Against Women are equally capacious and (to put it mildly) unconventional. Its publications define “domestic violence” as “a pattern of abusive behavior . . . used by one partner to gain
or maintain power and control over another,” including “[u]ndermining an individual’s sense of self-worth,” “name-calling,” and “damaging one’s relationship with his or her children.”
Then, Scalia attempts to explain why he believes the behavior above isn't domestic violence:
Of course these private organizations and the Department of Justice’s (nonprosecuting) Office are entitled to define “domestic violence” any way they want for their own purposes—purposes that can include (quite literally) giving all domestic behavior harmful to women a bad name. (What is more abhorrent than violence against women?) But when they (and the Court) impose their all embracing definition on the rest of us, they not only distort the law, they impoverish the language. When everything is domestic violence, nothing is. Congress will have to come up with a new word (I cannot imagine what it would be) to denote actual domestic violence. 
"Unlike dictionary publishers," Scalia continues, advocacy organizations like those who submitted friend of the court briefs for the case "have a vested interest in expanding the definition of “domestic violence” in order to broaden the base of individuals eligible for support services."

 Original article