Qua is Latin for acting in the capacity of, acting as, or in the manner of. After identifying a person, the word "qua" may be added to signify that the rest of the statement pertains to that person acting in the capacity of whatever title or position comes after "qua."
For example, in New Jersey v. Delaware, 552 U.S. 597, 600 (2008), “Virginia qua sovereign” means Virginia acted as a sovereign.
See also: sine qua non, Law Latin
[Last updated in August of 2023 by the Wex Definitions Team]