There was this point about, you know, the basic point there as well - this statute treats some parts of the country different from others, and what's the justification for that? Well, you know, I had eight million things to say about that, but he put it in such a sharp, excruciating way that it was just very hard to handle it effectively.

I had a great deal of independence from the president and the White House during the entirety of my five years. And I'm not sure exactly what that is, but our friend, Walter Dellinger, has a theory about it, and I think he's probably right. And the theory starts with the fact that I worked in the White House for a year and a half before coming over to the position of SG. And because of that, when I was nominated, there was some chatter out there that, "Oh. They're putting a political hack in. This has never happened before."

After a couple of years, I realized that this was actually true, that his gave me the ability to go to a different place and, hopefully, have a stronger impact.

Justice [Sonia]Sotomayor said, "Let's talk - you want to talk about the tax power."And I got like a 10-minute run on the tax power. And, boy, was I glad I did because I was able to get across this idea that, yes, this is a narrower ground on which you can affirm it. And I think everybody agrees. I think even the dissenting justices ultimately in the case agreed that, if Congress had expressly called it a tax, it would be indisputably constitutional.

The moot court process in our office when we get ready, we - everybody, including the SG, does two moot courts for each argument. And they are phenomenal, and they predict 90 percent of the questions that I get asked, at least 90 percent.

Very quickly the lawyers in the Justice Department pulled together a set of recommendations about how we ought to defend the law as a constitutional matter. And it was the lawyers in the Justice Department who thought that it was important to include the tax power argument as part of it.

If you've ever been in the West Wing, it's like a little rabbit warren. Everybody's crammed in there on top of each other, and you're eating breakfast, lunch, and dinner at the mess with people. And so you really get to know each other very well. So, I think they just weren't worried.