The First Amendment broadly prohibits the government from making laws that restrict freedom of speech. Political speech includes not just speech by the government or candidates for office, but also any discussion of social issues. Commercial speech, on the other hand, advertises a product or service for sale. The Supreme Court has interpreted the Constitution as providing stronger protection to political speakers than to advertisers.

Purpose and Intent

The purpose for the speech is perhaps the key difference between political and commercial speech. Political speech focuses on the public good, but commercial speech only benefits a single private entity -- the seller of the product or service advertised. While commercial speech aims at your wallet, political speech aims at your mind. Because functional democracy depends on the ability of the people to openly debate public issues and criticize government officials without fear, free political speech is judged to be more important than free commercial speech.

Constitutional Protection

Since political speech is more important than commercial speech, it stands to reason it would be entitled to the strongest protection the First Amendment can provide. Discussion and debate of issues of public concern can be restricted only in the rarest of circumstances, and the government must have a strong, compelling interest for doing so. Commercial speech is seen as having far less value, and thus is granted far less constitutional protection. In fact, until 1975 the Supreme Court held that commercial speech had no protection whatsoever under the First Amendment and governments could regulate it at will. While commercial speech has gained some protection, federal, state and local governments still have broad authority to restrict advertising provided regulation furthers a substantial interest, such as protecting the public from fraud.

The Right to Lie

Political speech has so much protection under the First Amendment that the government can't even make laws to keep people from lying about political issues. For example, a candidate for public office has the right to fabricate or distort his past voting record. Free speech relies on an informed electorate to uncover the truth, rather than allowing the government to restrict speech. Someone personally injured by defamatory political speech retains the right to sue the speaker for the resulting damage to his reputation. In contrast, false or misleading commercial speech has no First Amendment protection, and can be banned by federal, state or local law.

A Question of Context

The First Amendment only applies to government action. Private individuals or corporations cannot violate your First Amendment rights, and are free to regulate the speech of anyone under their authority. For example, a private school may have rules restricting teachers or students from discussing political issues. However, since public schools are government entities, they have more limited abilities to control the speech of their faculty and students. Public school students retain some rights to free speech, but school authorities do have the ability to limit those rights to maintain order and discipline within the school setting.