Only Virginia and Maine declined to sign the brief by the Kansas attorney general.
Albert Snyder sued over protests by the Kansas-based Westboro Baptist Church at his son's funeral in Maryland. The church, founded by Fred Phelps in 1955, pickets funerals because they believe war deaths are punishment for U.S. tolerance of homosexuality.
The Supreme Court has agreed to consider whether the protesters' message is protected by the First Amendment.
In the brief filed Tuesday, the states argued they have a compelling interest in protecting the sanctity of funerals.
Source says, "God hates assholes."