A more thorough explanation:

The Smith Act is a federal law that was passed in 1948. It makes it illegal to advocate or teach the violent overthrow of the government. This law is also known as the Anti-Sedition Act.

For example, if someone creates a website or writes a book that encourages people to use violence to overthrow the government, they could be charged with violating the Smith Act. However, if someone simply expresses their opinion that they don't like the government, that is not a violation of the Smith Act.

The Smith Act is aimed at preventing people from taking concrete actions to overthrow the government. It is not aimed at people who simply have different beliefs or opinions about the government.