New York’s criminal justice system has failed crime victims yet again — and its attorneys bear the lion’s share of the blame. 

Why aren’t the city’s prosecutors asking for mental competence exams — known internally as a Section 730.30 — more regularly at arraignments involving the mentally disturbed? Why aren’t public defenders requesting them on behalf of their mentally ill clients?

Ramon Rivera, the offender who allegedly went on a Manhattan stabbing spree Monday and killed three innocents, had a long recidivist history.

In all those many encounters, assistant district attorneys, Legal Aid lawyers and judges had to notice he wasn’t playing with a full deck.