There is an international human rights law aspect to Grutter v. Bollinger 1 and Gratz v. Bollinger 2 that might be missed by many lawyers and scholars who rarely consider any legal domain beyond the limits of the U.S. Constitution. Indeed, Grutter and Gratz reflect a trend in Supreme Court opinions to use international human rights sources in interpreting the Constitution.
David Weissbrodt, International Human Rights Law Perspective on Grutter and Gratz, 21 Const. Comment. 275 (2004), available at https://scholarship.law.umn.edu/faculty_articles/215.