But there’s one long-discussed tax that can help fix the subways, pay cops and teachers and maybe even lighten the tax burden on the rest of us without jeopardizing the city’s underlying tax base — while, bonus, beginning to correct a property tax system so skewed it hits mega-rich condominium owners with lower effective property tax rates than most middle-class New Yorkers. (Case in point: Hedge fund billionaire Ken Griffin will pay 0.22% on the $238 million Manhattan penthouse he bought early this year; Staten Island homeowners can pay as much as five times that. Disentangling the mess of a system is a Herculean lift, as we’ve written in a series of editorials.)