The owner of the copyright (i.e., in most cases, the true author) could sue the plagiarist in federal court for violation of the copyright. Any work created in the USA after 1st. Mar 1989 is automatically protected by copyright, even if there is no copyright notice attached to the work. 17 USC, Sub-Section 102, 401, and 405.

It is important to note that the addition of original material by the plagiarist in no way excuses the act of plagiarism. The focus is on what the plagiarist did wrong, not what the plagiarist did right. Trivial changes in copied text, in an attempt to avoid copyright infringement, are specifically prohibited by law in the USA:

• Nichols v. Universal Pictures Corp., 45 F.2d 119, 121 (2d Cir. 1930) ("It is of course essential to any protection of literary property ... that the right cannot be limited literally to the text, else a plagiarist would escape by immaterial variations.").

• Sheldon v. Metro-Goldwyn Pictures Corp., 81 F.2d 49, 56 (2d Cir. 1936) ("... no plagiarist can excuse the wrong by showing how much of his work he did not pirate.").

• A Columbia Pictures' promotional poster for a movie infringed the copyright of an illustration on the cover of a New Yorker magazine, although the details in the movie poster had been changed from the magazine cover (only the words "Hudson River" were the same in both items). The judge ruled that the movie poster was "substantially similar" to the magazine cover. Steinberg v. Columbia Pictures, 663 F.Supp. 706 (1987).

Beyond intellectual property issues (e.g., copyright and trademark), the plagiarist commits fraud. The plagiarist knows that he/she is not the true author of the work, yet the plagiarist willfully and deliberately puts his/her name on the work (thereby concealing the true author's name), then the plagiarist submits the work as an inducement to some kind of reward (e.g., good grade on a term paper, awarding a graduate degree for a thesis or dissertation, obtaining a scholarship, winning a prize in a science fair, etc).

Using phrases like "academic misconduct" to describe plagiarism is too sterile, too kind. Plagiarism is fraud.

Trademark and unfair competition law

Professors and research scientists are often hired, promoted, receive tenure, and are awarded salary increases on the basis of their scholarly publications. To measure the significance of scholarly publications, many administrators in colleges look at Science Citation Index to see how often a professor's work has been cited by others. Therefore, if 'D' plagiarizes 'V's' work – instead of D citing V's work – then V is potentially harmed by having fewer citations to V's work. On the other hand, D is unjustly enriched by receiving credit for a publication that was plagiarized, so D builds D's reputation with V's work.

Recognizing this harm, the true author could sue the plagiarist in federal court for "false designation of origin", 15 USC, Section 1125, since the plagiarist was misrepresenting someone else's work as his own. Similarly, there are also possible remedies under state unfair competition law. Restatement of the Law (Third) Unfair Competition, Sub-Section 2, 3(b), 5 (1995).

In every plagiarism case involving a student or professor, the court upheld the punishment imposed by the college/university/school. Further, the court often made gratuitous, pejorative comments about the bad character of the plagiarist, which show that it is unwise for a plagiarist to complain about how he/she was treated.

A judge in a federal court, noted that one attorney had plagiarized the Brief of the opposing attorney, then commented that opposing counsel had:

Plagiarism is a very serious crime, and research shows how plagiarism can haunt a person's reputation, even ten years later.