Who is Christopher J. Meade? The short answer: Acting Chief Counsel of the Treasury. Here's his bio.
Why does he matter? Well, it seems that White House counsel Kathryn Ruemmler met repeatedly with him three times last year -- including once before the election (September 27, 2012), according to Charles Johnson of the Daily Caller.
Given that Deputy Treasury Secretary Neal Wolin had been informed by the Inspector General about the IRS probe over the summer of 2012, it is almost inconceivable that Meade wouldn't have told Ruemmler about such a potentially disastrous political issue before the election.
So it seems that Mr. Meade has now bought himself a ticket to a congressional hearing. It would be interesting to what they discussed.
Incidentally, Johnson's piece references left-wing activism by Meade while he was at Princeton. We overlapped during our time there, and I don't really recall hearing about him. In fairness, though, by spring of '89, I had retired from my post at The Daily Princetonian and was busy writing my thesis.