The History of the Separation of Church and State in the US

While increasingly attacked by legal scholars and even some justices, the Lemon test was until very recently still the standard for lower courts to use in assessing establishment clause litigation. Twenty years ago, it provided the Justices with the precedent they used in Santa Fe v. Doe in holding unconstitutional the policy of allowing student-led prayers at school football games, because the practice had a religious, not secular, purpose. As recently as 2005, litigants specifically asked the court to overturn Lemon and the Justices refused to do so. In 2019, Justice Brett Kavanaugh, writing for himself alone, insisted that "the Lemon test is not good law." Justice Clarence Thomas said he would overrule the precedent. Finally, in 2022, they abandoned Lemon. In Kennedy v. Bremerton School District, by a 6-3 vote, the justices said the school district was wrong to fire a coach for ignoring orders not to lead midfield prayers after football games. Henceforth, they decreed, the courts in considering conflicts between the two religious freedom clauses of the First Amendment should use not the Lemontest but "historical practices and understandings."

https://www.historynet.com/history-separation-church-and-state/