Types of speech restrictions.
The Supreme Court has recognized several different types of laws that restrict speech, and subjects each type of law to a different level of scrutiny.
Content-based restrictions.
Content-based restrictions "are presumptively unconstitutional regardless of the government’s benign motive, content-neutral justification, or lack of animus toward the ideas contained in the regulated speech." Restrictions that require examining the content of speech to be applied must pass strict scrutiny.
Content-based restrictions can either discriminate based on viewpoint or subject matter. An example of a law regulating the subject matter of speech would be a city ordinance that forbids all picketing in front of a school except for labor picketing. This law would amount to subject matter discrimination because it favors one subject over another in deciding who it will allow to speak. An example of a law that regulates a speaker's viewpoint would be a policy of a government official who permitted ‘‘pro-life’’ proponents to speak on government property but banned ‘‘pro-choice’’ proponents because of their views would be engaged in ‘‘viewpoint discrimination.’’ Restrictions that apply to certain viewpoints but not others face the highest level of scrutiny, and are usually overturned, unless they fall into one of the court's special exceptions. An example of this is found in the United States Supreme Court's decision in Legal Services Corp. v Velazquez in 2001. In this case, the Court held that government subsidies cannot be used to discriminate against a specific instance of viewpoint advocacy.
The Court pointed out in Snyder v Phelps (2011) that one way to ascertain whether a restriction is content-based versus content-neutral is to consider if the speaker had delivered a different message under exactly the same circumstances: "A group of parishioners standing at the very spot where Westboro stood, holding signs that said 'God Bless America' and 'God Loves You,' would not have been subjected to liability. It was what Westboro said that exposed it to tort damages."
