Mental health counselling may prove to be a sine qua non to successfully re-integrating child soldiers into civilian life.

FORBES: For Child Soldiers, Every Day Is A Living Nightmare

Or to put it another way, banking union might be a precursor to the kind of fiscal and balance-sheet union that is widely regarded as the sine qua non of eurozone survival, but that supposedly vital financial union has not happened yet.

BBC: Eurozone banking union that works for Britain?