Welcome to Supreme Court Brief and the last day of the December argument session. This morning the justices hear another chapter in their continuing separation-of-powers review, this one involving the Federal Housing Finance Agency. Court-appointed amicus Aaron Nielson makes his high court debut. The court's first Native American clerk shares her experiences and thoughts on assumptions and diversity. Plus: A look at the clash between religion and public health. Thanks for reading, and your feedback is welcome and appreciated. Contact Marcia Coyle at [email protected] and follow her on Twitter @MarciaCoyle. And contact Tony Mauro at [email protected] and on Twitter @Tonymauro.