Regulators are making clear that they know what they don’t know. So in addition to traditional measures, they are also going to emphasize the “leverage ratio.” That’s good news, because the leverage ratio doesn’t allow for such accounting sleights-of-hand as adjusting the value of assets for their perceived riskiness. In that game, some investments — say, picking purely randomly, top-rated mortgage securities or Greek government debt — could be judged less risky than other assets. Can the Banks be Regulated