A Supreme Court justice is not required to take part in every case that reaches the court.
However, all nine of them did recently sign a "statement on ethics principles and practices" that said they would provide a reason for being absent when one of more of the justices decides not to take part in a case.
About a week ago, Justice Elana Kagan became the first member of the court to explain herself. She said that her previous employment in Barack Obama's administration kept her out of the appeal of a death row inmate in Florida.
Justice Samuel Alito, however, did NOT indicate why he wasn't present when the court turned away an appeal from energy companies.
Reports indicate that Alito owns between $15,000 and $50,000 in one of the companies that appealed, but Alito did not say that was the reason publicly.
What do you think, should justices have to explain themselves when they are absent? Do Americans need to know what's going on here?