The SCOTUS has ruled to allow government meetings to include prayers, even if those prayers are exclusive to a specific religion. I do actually agree with Justice Kennedy that any attempt to craft a non-sectarian prayer would involve an unacceptable level of government interference in religion. But the answer is to avoid public prayers at government meetings altogether, not to allow sectarian prayers. In a religiously pluralistic society, any sectarian prayer is going to exclude someone. And if you try to include everyone, you get Baphomets.
I’m strongly of the opinion that intermingling religion and government is as harmful to religion as it is to government. Those who push for more religion in government are in for a nasty surprise if we end up like Denmark, where 78% of people are members of the state church, but only 28% of people believe in God. As silly as the Oklahoma City “Satanic monument” is (and the Satanists know they are being silly), it makes an important point: when you give religion the force of being “official,” you can’t guarantee it will always be your religion. Before involving the government in religion, ask yourself, WWALVD? What would Anton LaVey do, if his religion had this official sanction? If you don’t like the answer, it’s probably not worth it.