One thousand more cops underground won’t make or keep the subways safe. Nor can 2,000 or 3,000 — because at its root, the cause of many random, dangerous acts in the subway is not a criminal justice problem. The victims of Jose Gonzalez, James Melbourne, Rigoberto Astwood Lopez, like many others, were harmed because our mental health system failed to treat people living with the most serious forms of mental illness before they became violent. Amending the standard for involuntary commitment, as called for by Gov. Cuomo, is one reform needed to begin to fix the system.