This first analysis will have two components. The first component is an account of how many questions each side received. The rule of thumb — the side getting the most questions from the bench loses.
I have two counts: the first being mere interruptions (as noted in the transcript) and the second being a more careful count of actual questions (and by questions I include interjections and statements).
Count 1 (total interruptions): Petitioner side (both Blatt and Clement) interrupted 71 times; Respondent side (both Rothfield and Kneedler) interrupted 72 times. Blatt (arguing 20 minutes, including rebuttal), interrupted 59 times; Clement (arguing 10 minutes, plus additional time granted by Roberts, C.J.) interrupted 13 times). Rothfield (arguing 20 minutes, plus additional time granted by Roberts, C.J.) interrupted 53 times. Kneedler (arguing 10 minutes) interrupted 19 times.
Count 2 (total questions): Petitioner side — 57 questions; Respondent side — 66 questions.
In either count, the petitioner has a slight edge. Based on questions and interruptions in total, it is clear that Paul Clement (to whom the Court granted a short period of extra time) was the most successful in oral argument, followed by Charles Rothfield. Both Lisa Blatt and, especially, Ed Kneedler, faced more scrutiny than did the others.
The second component is a quick look at whether this case will be decided on constitutional/federal common law grounds or statutory interpretation grounds. This is more important to me than who wins, even. As those of you who heard my talk at Fed Bar last Thursday, I believe this case is a winner for Indian country overall if it is decided on statutory interpretation grounds, even if the Cherokee Nation and the Father lose, because it will mean that the Indian Child Welfare Act survives to fight again another day. With a few exceptions, mostly relating to questions from the Chief Justice and Justice Scalia, constitutional/federal common law questions rarely came into the discussion today, even during Mr. Clement’s portion of argument (he had raised questions on the constitutionality of ICWA). However, both Mr. Clement (who raised then-DOJ lawyer Patricia Wald’s constitutionality analysis), and Ms. Blatt (who offered up a canned attack on the broadest possible implications of the case at the end), both raised the question, to be sure. Even so, the vast, vast majority of the discussion involved the interpretation of ICWA, not the constitutionality of ICWA.
So, given these factors, my prediction is that the petitioners stand a better chance to win, but the Indian Child Welfare Act stand a good chance of survival.
Kate Fort and I will be posting more on the argument as the day moves on.
Turtle Talk 
Not sure what to make of the curious discussion with Rothfield concerning the blood quantum of the child and the Chief Justice’s hypothetical tribe that recognizes non-biological Indians as tribal members. Interestingly, during this discussion, Scalia is convinced that federal law requires blood quantum, and therefore the hypothetical cannot exist. Another justice chimes in to describe the father’s ancestry as originating at the time of George Washington’s father. How much does the perception of the blood quantum of the father and child and the Cherokee Nation’s membership criteria affect this case?
It is most curious. As to Justice Scalia’s notion, I don’t know where it comes from. If the relationship between tribe-members and the federal government is a political one, based on the sovereignty of tribal governments and the tribe’s membership criteria, where does the notion arise that tribe members must be racially Indian? (I recognize the Morton doctrine is logically incoherent on this point—the BIA hiring preference expressly incorporates a blood quantum requirement, but describes it as a purely political, as opposed to racial, classification.)
Does Congress, the BIA, or the Supreme Court, get to set a blood quantum requirement for tribal membership, at least insofar as federal law is concerned? God save us.
I think what Scalia was possibly referencing was how we define an Indian in cases like US v. Rogers and US v. Antelope. I think what he is saying is there is an ethnic component to the racial classification. He, of course, is confusing cases if he is thinking of these since they had to do with criminal jurisdiction and not tribal enrollment. But he did author Hicks, so who knows.