The US Supreme Court is due to begin considering whether sportswear giant Nike can be sued for allegedly misleading US consumers over the production of its sports shoes.
Nike argues its claims are protected as free speech
The company has been accused of deceiving the public by denying its shoes were made under sweatshop conditions in Asia.
Nike says it should be allowed to defend its business practices and has the right to free speech under the First Amendment of the US constitution.
The outcome is seen as having huge implications for what businesses may or may not be able to comment on in future.
The case against Nike was brought five years ago in California by consumer activist Marc Kasky, who said it had misled the public about conditions for its workers in Vietnam, China and Indonesia.
The firm was said to have mounted a false advertising and public relations campaign, portraying itself as a "model of corporate responsibility" in an effort to boost sales.
California's highest court ruled last year that Nike's corporate statements could be interpreted as commercial speech and said the case could go to trial.
Speech is commercial in its content if it is likely to influence consumers in their commercial decisions... For a significant segment of the buying public, labour practices do matter in making consumer choices
California Supreme Court ruling
The company denies the claims, and has taken the case to the Supreme Court arguing its remarks were not intended to sell its products but to comment on an issue of public interest.
It says the case should be dismissed because all its statements were part of an international media debate on issues of public interest, and should be protected as free speech.
According to Reuters news agency, Nike has the support of several big businesses, the news media, the American Civil Liberties Union and the nation's largest group of unions.
Mr Kasky is backed by California and 17 other states, four members of the US House of Representatives and environmental, consumer and human rights groups who oppose sweatshop conditions.
After hearing arguments in the case beginning on Wednesday, the Supreme Court is expected rule at the end of June.