[Peter from Rutland]

I believe it specifically that there will be no official religion sanctioned by the government.

[MrB]

The context of the establishment clause, as all good FReepers well know, is the Church of England.

When you want to know what not establishing a religion means, look to the C of E, and say “not that”. A coach saying a prayer before a game is not establishing the analog of the Church of England.