Aug. 21: Mr. Obama devotes his weekly radio address to the threat of “attack ads run by shadowy groups with harmless-sounding names. We don’t know who’s behind these ads and we don’t know who’s paying for them. . . . You don’t know if it’s a foreign-controlled corporation. . . . The only people who don’t want to disclose the truth are people with something to hide.”

Week of Aug. 23: The New Yorker’s Jane Mayer authors a hit piece on the Koch brothers, entitled “Covert Operations,” in which she accuses them of funding “political front groups.” The piece repeats the White House theme, with Ms. Mayer claiming the Kochs have created “slippery organizations with generic-sounding names” that have “made it difficult to ascertain the extent of their influence in Washington.”

Aug. 27: White House economist Austan Goolsbee, in a background briefing with reporters, accuses Koch industries of being a pass-through entity that does “not pay corporate income tax.” The Treasury inspector general investigates how it is that Mr. Goolsbee might have confidential tax information. The report has never been released.