"Hey, we really can't keep up this system of just letting anyone graze sheep on the commons willy-nilly. Eventually it'll get overgrazed and produce nothing. To

"Hey, we really can't keep up this system of just letting anyone graze sheep on the commons willy-nilly. Eventually it'll get overgrazed and produce nothing. To prevent that catastrophe, we need to move to a system where total grazing is limited to a sustainable level." 'Well, then why are you grazing your sheep on the commons? Checkmate.'