In the upcoming Arizona immigration law Supreme Court case, President Obama will need the votes of four justices to achieve victory and invalidate its key provisions.
Why not five? Because Justice Elena Kagan, who was the administration's Solicitor General when the lawsuit was filed, has recused herself. That leaves eight justices to hear the case. And the rules are that a hypothetical 4-4 tie would affirm the Ninth Circuit Court of Appeals' holding that major parts of the law are unconstitutional.
A 4-4 tie would mean the ruling does not apply to similar laws in other states, however, and would leave open the possibility of future lawsuits to settle the larger constitutional questions.
So, how does the math look now?
"The government can count on the votes of [Justices] Sotomayor, Breyer, and Ginsburg. [Justice] Thomas, who has argued against implied preemption in the past, is likely to side with Arizona," said Adam Winkler, a professor at UCLA School of Law. "That leaves [Justices] Roberts, Scalia, Kennedy, and Alito in play."