When teaching federal courts, I sometimes find that students are slow to care about legal issues that initially seem picayune, hyper-technical, and unrelated to real-world concerns. It takes hard work to engage students in discussion of United States v. Klein,1 notwithstanding its apparent articulation of a foundational separation of powers principle that Congress may not dictate a "rule of decision" governing a case in federal court. A Civil War-era decision about the distribution of war spoils, one the Supreme Court has hardly ever cited since and then only to distinguish it, in cases involving takings and spotted owls? Yawn.
Caminker, Evan H. "Schiavo and Klein (Symposium)." Const. Comment. 22, no. 3 (2005): 529-51.