He signed my book, and as he handed it back to me, he said something I'll never forget: "You know, when it comes to Indian law, most of the time we're just making it up." This was a shock. My first encounter with the Supreme Court over a decade earlier had convinced me of their legal omnipotence, and although my subsequent education had taught me to be more critical, especially with regard to Indian law, it was still a surprise to hear a justice admit as much.

Now, with the opportunity to appoint a justice to fill Scalia's untimely vacancy, I can only hope that President Obama will keep one thing in mind. It's something we already know, but that the court is characteristically slow to reflect: Diversity is important. Not just in terms of gender, race or geography, but diversity of experience. Understanding Indian law isn't about niche expertise or showing favoritism to a particular political group. Rather, it's about valuing the implications of a decision beyond their "made up" logical conclusions and appreciating them for their historical significance and tangible impact on the lives of nearly three million American Indian people, their neighbors, and the states in which they live.

The Indian law cases that land before the Supreme Court have broad implications for real human beings subject to an inordinate amount of federal discretion. So far this term, the court has already taken four. The implications of these decisions will determine, for example, if a tribe has civil jurisdiction over a non-Indian who sexually assaulted a teenager on tribal land, and whether or not Congress' efforts to confront epidemic levels of domestic violence in Indian Country will be thwarted by a lack of respect for the decisions of tribal courts. If the court is truly making anything up, it's the increasing limitations on the breadth and reach of tribal sovereignty, which includes the ability of a tribe to ensure the health and safety of its people. And that's important enough that even a fifth grader could understand.