I generally do not like slippery slope arguments, but the HS graduation scenario might be a good place to apply that principle. If we are going to allow someone to pray to Jesus at a government-sponsored event, then don't we have to give equal time to voodoo priests, atheists, and everything else anyone can think of?

In many communities a prayer to Jesus would be just the right thing at that sort of event, but I don't think the government can sponsor it.