The voucher program was meant to close the gap between the haves and the have-nots — the families who could already afford to send their children to private school and those who just couldn’t afford the tuition. But once the slots are filled, that dilemma returns — at least for those students who aren’t lucky enough to nab an open spot in a private classroom. They’ll be left to attend public schools that already complain they’ve been hurt by the exodus of students — and therefore money — from their buildings.