When the State Department originally turned over the Clinton emails earlier this year, Gowdy asked State to certify that it was turning over all of Clinton’s communications related to Libya. State officials would not do that, arguing they only had what Clinton gave them, although they accepted Clinton’s word that they had everything.

Also baffling to investigators is what is going on with Blumenthal. The materials he turned over could undermine Clinton’s claim of having given all of her work-related emails to the State Department. Yet Blumenthal, a longtime Clinton acolyte who owes his livelihood to the Clintons — during the time in question, he received $10,000 a month from the Clinton Foundation and another $10,000 from a Clinton-related media watchdog group — seems the last person in the world who would give Republicans anything they could use against Clinton. So that is another mystery.

This latest tangle illustrates the difficulty Gowdy and his fellow lawmakers face in trying to figure out the Benghazi story. Yes, they have made progress — remember, the world would not even know about Clinton’s secret email system had it not been for Gowdy’s committee. But they face a daunting challenge in getting information not only from Clinton but from her inner circle and the State Department. It’s taken a long time to get this far, and there is still quite a way to go.