The U.S. Supreme Court case KP Permanent Make-Up, Inc. v. Lasting Impression I, Inc., et al., 2004 revolved around the issue of trademark infringement and fair use defense in advertising language. Lasting Impression held a registered trademark for the term "microcolor" and sued KP Permanent Make-Up for using the same term in their advertisements without permission, claiming it was an infringement on their rights as per Lanham Act (Trademark law). However, KP argued that they were merely using descriptive terms to accurately describe their product which is allowed under 'fair use'. The court ruled in favor of KP Permanent Make-up stating that a company could invoke 'fair use' even if consumer confusion might result from such usage; thus clarifying that likelihood of confusion does not negate fair use defense under Trademark Law.

In the dissenting opinion for KP Permanent Make-Up, Inc. v. Lasting Impression I, Inc., Justice Kennedy argued that a defendant in a trademark infringement case should bear the burden of proving fair use as an affirmative defense. He disagreed with the majority's conclusion that it is not necessary for defendants to show there is no likelihood of consumer confusion about origin or sponsorship due to their use of plaintiff’s mark. According to him, this interpretation undermines the Lanham Act's primary goal: protecting consumers and trademark owners from misleading uses of marks on competing goods or services. He also expressed concern that shifting this burden onto plaintiffs would make it more difficult for them to protect their trademarks against unauthorized uses which could potentially confuse consumers.