In 2016 the LCMS put out a bible study on the relationship between church and state. It was in response to Obama Care at the time but it still applies. The videos can be viewed on their own or with the bible study material.
Session 1 Is That A Crack In The Wall Of Separation?
Session 2 What Did The Founders Have In Mind?
Session 3 Is America A Christian Nation?
Session 4 Collision And Cooperation