The fair-value benchmark is the exchange rate that leaves burgers costing the same in America as elsewhere.

Today, if the bad bank pays above the fair-market value, it would raise the cost to taxpayers, imperil its political legitimacy, and deprive the market of badly needed transparency.

This reflects that any estimate of fair value is just that: an estimate, not a precise figure, so the margin of safety provides a much-needed cushion against errors and misfortunes.

Other tactics exist to "do the right thing" for individual students by moving them from one class to another, but none does anything to address the fundamental unfairness of the process.