The battle to control the Senate was a proving ground for the new Citizens United politics. Outside groups unleashed heavily funded barrages of attack ads meant to help elect candidates while letting them keep their distance from the nastiness.
In Ohio and Virginia, the tactic failed in rather dramatic ways, as Republicans backed by secretly financed ads failed to beat seemingly vulnerable Democrats.
Since April, most of the TV ads supporting Republican presidential nominee Mitt Romney have come from outside groups, not from Romney's own campaign. And those groups raised more than half of their money from secret donors, according to a six-month study of ads.