The phrase "under god" in the Pledge of Allegience is unconstitutional.
The insertion of religious phrases into daily life in public schools was deemed unconstitutional by Engel v Vitale, and was affirmed by many, many cases to follow.
The fact that the phrase was instituted by a democratically elected Congress does not change the fact that it was illegal to do so:
"Our Founders were no more willing to let the content of their prayers and their privilege of praying whenever they pleased be influenced by the ballot box than they were to let these vital matters of personal conscience depend on the succession of monarchs." - Justice Black, majority opinion, Engel v. Vitale
I think that a lot of people will be surprised when this case comes before the SC and is decided in favor of the petitioners by a margin of 9-0. There's no Potter Stewarts left on the court.