Former IRS commissioner Douglas Shulman doesn't think he has to apologize for the wrongdoing that occurred at the IRS on his watch, and he repeatedly refused to do so at a Senate Finance Committee hearing on Tuesday.

We'll see how long that lasts.

Shulman at several points during Tuesday's hearing expressed "regret" that conservative groups were improperly targeted by the IRS over the last three years, even saying he was "deeply saddened" by it. But when asked whether he would apologize, Shulman balked.

"I certainly am not personally responsible for making a list that had inappropriate criteria on it,” Shulman told Rep. John Cornyn (R-Texas), adding: ”With that said, this happened on my watch, and I very much regret that this happened on my watch.”

Shulman's desire to escape personal culpability for what happened is understandable, but senators weren't asking him to admit to personally being involved. They were simply seeking their pound of flesh -- acknowledgment that leaders bear some responsibility for what their employees do. Shulman wouldn't even go that far.

The quasi-apology, needless to say, didn't satisfy the committee, with both Democrats and Republicans seeking a fuller mea culpa. It didn't come.

"I have to say, listening — and I’ve been here for virtually every moment of this hearing — I wish there was more of a sense of outrage or at least more contrition than demonstrated by both you, Mr. Shulman, and you, Mr. Miller, in light of what’s happened here,” said Sen. Bob Casey (D-Pa.), referring to another former IRS head, Steven Miller.

But, in fact, Miller had apologized -- including in his opening statement at Tuesday's hearing.

Even Lois Lerner, the head of the IRS's tax-exempt organizations division whose initial response to the scandal was widely panned (think: "I'm not good at math"), has apologized in no uncertain terms.

“The IRS would like to apologize for that,” she said when she first discussed the matter at a legal conference two Fridays ago.

On Wednesday morning, Shulman -- who led the IRS through much of the time period during which the wrongdoing took place -- is scheduled to sit next to Lerner at the witness table of the House Oversight and Government Reform Committee.

And the questioners won't be as gentle and statesman-like as the Senate Finance Committee members were on Tuesday.

The countdown to Shulman's fuller apology begins now.