But an overzealous prosecutor can bungle even an open-and-shut case, and that’s what Democrats hope to portray Darrell Issa, the chairman of the House Oversight and Government Reform committee and the President’s self-styled nemesis. For years, Issa has launched a series of probes into alleged White House malfeasance, from the “Fast and Furious” gun-running controversy to loans the Department of Energy made to the failed green-energy company Solyndra. In both instances, Issa promised scalps — only to see the alleged perpetraters cleared by independent investigators. Now Democrats are pointing to his habit of claiming conspiracy, as well as a series of intemperate remarks Issa has made about the IRS case, in an attempt to deflect attention from the scandal by discrediting the inquisitor…

Senate Republicans also think Issa is getting ahead of himself. “I don’t believe this was something thought up in the Cincinnati office, but I have no evidence that goes to the White House,” Republican Senator Lindsey Graham said Sunday on Fox News. “You can go too far,” he added. “Jay Carney is not the issue here.” Graham’s partner in crime, Arizona Senator John McCain, said Republicans should “let the facts come out” rather than lob insults…

Privately, some Republicans fret that Issa’s overzealousness could blur the lines between the committee’s legitimate oversight role and partisan witch-hunting. And even Democrats wonder why Issa won’t let the investigation run its course. “This isn’t good for us, but it’s not as bad as he’s making it out to be either,” says one longtime Democratic operative. But like Issa, Democrats probably don’t know yet where the probe will lead. And their scramble to target Issa suggests they’re searching for their own scapegoat in case it’s nowhere good.