In recent years, the U.S. Supreme Court’s treatment of commercial speech has undergone transformations, from total non-protection under the First Amendment to less protection or even to qualified protection. However, why is commercial speech entitled to only less protection? The
transformations indicate that commercial speech may not be less valuable than political speech according to truth or individual rationale but not democratic rationale. Even though the Court has not been unanimous on the issue, there are plenty of important precedents and studies in the U.S. Despite significant alterations in judicial outcomes in recent years, certain aspects of commercial speech may be much the same as before, and the theoretical justification for this deferential approach has thus far not been clearly spelled out. Compared with that, Judicial Yuan interpretations and academic discussions on commercial speech are still limited in Taiwan. This paper will sum up the main treatments of the Courts and review the main claims and viewpoints of that topic in both countries.