Naiel Nassar, M.D. served as an Assistant Professor of Internal Medicine and Associate Medical Director with the University of Texas Southwestern Medical Center and complained that he allegedly was being harassed by a Supervisor, Dr. Levine. He later got a job with Parkland, an affiliated clinic, and submitted a letter of resignation in which he asserted that his "primary reason" for resigning was because of Dr. Levine's harassing and discriminatory behavior. Shortly thereafter, Parkland withdrew its job offer.
Dr. Nassar brought suit in federal court, accusing UTSW of orchestrating Parkland's refusal to hire him in retaliation for his discrimination complaints, in violation of Title VII. The Supreme Court held that the appropriate standard of proof in retaliation cases was the narrower “but for” causation standard. The American Council on Education (ACE) filed an amicus brief in support of UTSW arguing that AAUP policies supported the higher burden of proof. The AAUP filed an amicus brief in response, arguing that ACE had misinterpreted AAUP policies and that in fact AAUP policies supported the "but for" standard in retaliation cases.