Release of all his tax returns back to 1999 may not be necessary. The minimum information voters deserve is reliable assurance that active investor status was not claimed for Bain Capital or related entities by Romney for 1999, 2000, or 2001. If there was no active claim then tax evasion is unlikely.
A panel of discrete experts trusted by everyone could settle the active/passive issue by looking at the returns and holding a press conference. I suggest Erskine Bowles and Alan Simpson backed up by a team of tax experts. The panel could also summarize year-by-year the effective tax rate paid by Mr. Romney. If the rate is very low, he may be proud of his tax accomplishment but must take responsibility for how little he contributes to America’s needs relative to his financial capacity.