...If confirmed by the Senate as a justice, Kagan would have to sit out high court review of the government's decade-old racketeering lawsuit against cigarette makers. That's because she already has taken sides as solicitor general, signing the Obama administration's Supreme Court brief in the case — an automatic disqualifier.

Kagan is expected to step aside from 11 of the 24 cases the court has so far agreed to hear beginning in October.

A justice's decision not to participate in a case, called a recusal, can have a dramatic effect on a nine-person court. The court has split 4-4 on several occasions in recent years when justices did not take part in a case because they owned stock in an affected company, had a relative involved in some way or had participated in the case either as a lawyer or judge....