Is Holden Caulfield still only J.D. Salinger’s character?

J.D. Salinger recently filed a lawsuit (complaint (pdf)) seeking to block the publication of 60 Years Later: Coming through the Rye, an unathorized sequel to Catcher in the Rye, on the grounds it infringes Salinger’s copyright in the novel and in Holden Caulfield, the “narrator and essence of that novel.”

It’s an interesting case.  In SunTrust Bank v Houghton Mifflin Co., 268 F.3d 1257, 60 U.S.P.Q. 2d 1225, 14 F.L.W. Fed. C, 1391 (2001, 11th Cir.), rehearing denied en ban, 275 F3d 58 (11th Cir. 2001), the owners of the copyright to Gone With the Wind sued the publisher that owned the rights toThe Wind Done Gone, a critique of the depiction of slavery and the Civil-War era American South and that used and drew upon the characters and story line from Gone with the Wind.  The court ordered the lawsuit dismissed because The Wind Done Gone‘s use of the characters and story line from Gone with the Wind constituted fair use.  The court’s conclusion was that TWDG was a protected parody of GWTW because one of its principal purposes was to critique the worldview advanced  by GWTW:

TWDG is more than an abstract, pure f ictional work. It is principally and purposefully a critical statement that seeks to rebut and destroy the perspective, judgments, and mythology of GWTW. Randall’s literary goal is to explode the romantic, idealized portrait of the antebellum South during and after the Civil War. In the world of GWTW, the white characters comprise a noble aristocracy whose idyllic existence is upset only by the intrusion of Yankee soldiers, and, eventually, by the liberation of the black slaves. Through her characters as well as through direct narration, Mitchell describes how both blacks and whites were purportedly better off in the days of slavery: “The more I see of emancipation the more criminal I think it is. It’s just ruined the darkies,” says Scarlett O’Hara.GWTW at 639. Free blacks are described as “creatures of small intelligence . . . [l]ike monkeys or small children turned loose among treasured objects whose value is beyond their comprehension, they ran wild – either from perverse pleasure in destruction or simply because of their ignorance.” Id. at 654. Blacks elected to the legislature are described as spending “most of their time eating goobers and easing their unaccustomed feet into and out of new shoes.” Id. at 904.

It seems that any sequel is bound to comment on the original in one way or another. Does that mean any sequel is a non-infringing fair use of the original work? I doubt it, but where would the line go between a sequel sufficiently critical of the original and a sequel that merely exploits the value the author created in the original?