In the court of public opinion, Disney may well lose its battle with Scarlett Johansson.

But the legal question is important, carrying implications for business well beyond the borders of the Marvel Cinematic Universe and the actor who has for more than a decade portrayed the character known as Black Widow.

Johansson claims that the Walt Disney Co. breached her contract last month when it released the eponymous film simultaneously in movie theaters and on the Disney+ streaming service. Because her compensation depends in large part on how well the film does on the big screen, Johansson argues, the availability of the movie at home reduces her potential earnings.