The Very Senior White House Person who threatened Bob Woodward was Gene Sperling, economic adviser to the President.

Politico reveals the name and presents the text of the email:

I apologize for raising my voice in our conversation today. My bad. 

So there's also that conversation, which involved yelling, and we don't have the transcript of it.

I do understand your problems with a couple of our statements in the fall — but feel on the other hand that you focus on a few specific trees that gives a very wrong perception of the forest. But perhaps we will just not see eye to eye here.

But I do truly believe you should rethink your comment about saying saying that Potus asking for revenues is moving the goal post. 

These Washington folk are fond of clichés — moving the goal posts, forest for the trees, seeing eye to eye. I would lose my mind!

I know you may not believe this...

As a reader, I translate that into I don't even believe what I'm about to say myself.

... but as a friend...

More filler and one more thing that's not believable, but maybe there's a Washington kind of "friendship" that we outsiders don't quite get.

... I think you will regret staking out that claim. The idea that the sequester was to force both sides to go back to try at a big or grand barain [sic] with a mix of entitlements and revenues (even if there were serious disagreements on composition) was part of the DNA of the thing from the start....

If "I think you will regret" is supposed to be the threatening part, the accusation is weak. Sperling is bullshitting — blathering the administration's position wordily — but only explicitly saying Woodwood is wrong and predicting that Woodward will ultimately agree that the President didn't "move the goalposts." But I didn't hear the tone and content of the earlier discussion. And Sperling's apology and subsequent verbosity — I'm eliding a chunk of it — suggest that he knows he crossed a line.

The email ends:

Not out to argue and argue on this latter point.

Which of course he just did.

Just my sincere advice. Your call obviously.

My apologies again for raising my voice on the call with you. Feel bad about that and truly apologize.

That sounds pretty meek, but — again — implies that he was awful earlier.

Here's Woodward's response:

Gene: You do not ever have to apologize to me. You get wound up because you are making your points and you believe them. This is all part of a serious discussion. I for one welcome a little heat; there should more given the importance. I also welcome your personal advice. I am listening. I know you lived all this. My partial advantage is that I talked extensively with all involved...

So, Woodward is conciliatory and seemingly all about maintaining his continued access to Sperling. What happened next that motivated Woodward to go on TV and say he was threatened and that it was "madness"?

Woodward is a master at this game, so let's figure out what he's doing. He said he welcomes a little heat. Then he makes some big heat of his own. Why?