To review: After President Obama blamed “two Dilberts in Cincinnati,” an inspector general’s report found that high-level IRS officials in Washington were involved in directing additional scrutiny toward tea party groups seeking tax exemptions. Lerner admitted as much, before taking the Fifth Amendment to avoid testifying before the House oversight committee. The House of Representatives held her in contempt. And now the evidence of possible communications between Lerner and other agencies (including the White House) has gone missing under suspicious circumstances. It could be a regrettable series of rogue operations, IRS management failures and technical glitches. Or they could be taking us for fools.

If there was any political motivation for this abuse of power, it is a form of corruption — the kind of thing Americans like to criticize in countries they regard as less developed. And the circumstantial evidence is strong. This wave of heightened IRS scrutiny came after Democratic senators, warning of possible abuses spawned by the Supreme Court’s Citizens United decision, demanded additional IRS scrutiny of nonprofit political groups. Because evidence of political influence is both plausible and circumstantial, a special counsel is needed to sort out the truth.