While Washington is atwitter over the burgeoning Joe Sestak scandal, the curious departure of Minerals Management Service head Liz Birnbaum Thursday appears to be a growing story in its own right. It appears that not only did President Barack Obama legitimately not know whether Birnbaum’s exit was a firing or a resignation, but her boss Ken Salazar was perhaps not truthful in testifying before Congress about the change in her job status.

Birnbaum had a rough go of it in testimony before a House committee on Wednesday, testimony which revealed that she apparently wasn’t aware that MMS inspectors are unionized and that under her watch a father-and-son inspection team (MMS inspectors work in pairs so as to cross-check the results of their inspections) was the last MMS presence on the Deepwater Horizon rig before it exploded and sank.

That testimony was the last the Harvard-trained environmental lawyer would give before vacating her position. On Thursday she was scheduled to appear before a house subcommittee chaired by Rep. Jim Moran (D-VA), but called to tell Moran that she would not be testifying. Birnbaum would not tell Moran why she wasn’t coming.

A couple of hours later, Salazar appeared at the hearing.

Minutes later, after news reports surfaced that President Barack Obama had fired Birnbaum, Salazar insisted that she had resigned “on her own volition.”

The secretary defended Birnbaum, calling her a strong leader and good public servant who helped “fix a broken system” at the agency, whose employees have been accused of engaging in sweetheart deals with oil executives and swapping pornography-filled e-mails during the Bush administration.

“She resigned today on her own terms and on her own volition,” Salazar told Moran and other members of the House Appropriations subcommittee that focuses on the interior and the environment.

Moran has told reporters that Salazar should be taken at his word. Blogger “Streiff” at Redstate.com has information which would indicate otherwise.

Interior Secretary Ken Salazar summoned Birnbaum to his office before the Congressional hearings before Representative Jim Moran’s subcommittee to let her know that she was not to attend the hearing and that her presence at the hearing and his association with her was somewhat less than useful to either Salazar or the Administration.

According to our sources Birnbaum, who is well known for being foul-mouthed (as well as aesthetically challenged), was underwhelmed by Salazar’s point of view and replied, “**** you.”

What followed was a frank and unvarnished exchange of opinions. At some point Department of Interior security personnel arrived and escorted Birnbaum from the premises. Salazar was accompanied to the hearing by Deputy Interior Secretary David Hayes.

The Redstate.com account is largely corroborated by a New York Times report on Birnbaum’s ouster which makes the case that Birnbaum is a sacrifice to the media gods on this spill and a scapegoat for the horrid performance of the MMS over the years…

Someone from Interior Secretary Ken Salazar’s office called and said the secretary did not want her to attend the House hearing. Following a harsh New York Times profile that highlighted her low profile in the crisis, that might have seemed like a bad omen.

But Birnbaum, the former veteran congressional staffer, was worried more about stiffing a committee chairman than what this meant for her job. She called Rep. Jim Moran (D-Va.), chairman of the Interior Appropriations Subcommittee, where she was supposed to testify, to tell him she would not be appearing.

Moran called Salazar, who then walked out of his sixth-floor hallway with Deputy Secretary David Hayes. They went one floor down and four hallways over to Birnbaum’s office in 5400 corridor of Main Interior and asked her to resign.

Hayes, who has taken the lead for Salazar on the spill, testified in Birnbaum’s place at the hearing.

At the start of the hearing, Moran gingerly brought up the question of why Birnbaum was absent. Salazar ducked the question at first. Moran would explain later that she had not actually resigned at that point. But a few minutes later, as news alerts flashed on Blackberrys around the Capitol that Birnbaum had been fired, Salazar announced to the committee that she had resigned, “on her own terms and of her own volition.”

And Birnbaum’s resignation letter reads very much like a forced resignation – and a relatively acrimonious one at that. It’s six lines long and it is anything but flowery.

Which begs the question – if Salazar said that Birnbaum resigned “on her own terms and her own volition,” was that a lie? It certainly appears that is the case. Birnbaum is probably the only person who can answer the question for sure. If Salazar did lie, though, he did so under oath. In light of his performance as Secretary of the Interior to date, it might be worthwhile for Republican members of Congress to begin attempting to get to the bottom of that question.