Complex sentence: The Chief Justice's opinion asserts the term "under God" does not endorse or establish religion but it actually asserts that the term merely acknowledges the nation's religious heritage, in particular the role of religion for the Founding Fathers of the United States.
Split into simpler sentences: The Chief Justice's opinion asserts the term "under God" does not endorse or establish religion. Instead, they asserted that the term merely acknowledges the nation's religious heritage, in particular the role of religion for the Founding Fathers of the United States.