The tragedy is undeniable. Kansas City Chiefs linebacker Jovan Belcher fatally shot his girlfriend, Kasandra Perkins, Saturday morning in front of his own mother while the couple’s three-month old daughter slept in another room. Belcher  then drove to Arrowhead Stadium, where, after thanking his coach and general manager  for giving him a chance to play in the NFL, he shot himself to death, as the two men looked on.

Ultimately, we’ll never know what Belcher was thinking or feeling when he killed his girlfriend and then himself. The couple had been arguing but we don’t know about what. What we do know, though, is that neither internal problems in the couple’s relationship nor Belcher’s internal psychology can explain the horrific events, but ...