From the article:
Conzatti does not advocate for states to put their stamp of approval on one specific denomination but he does draw a line between “historic Christianity,” based on the Apostles’ and Nicene Creeds, and the faith of Latter-day Saints.
I notice that apparently there is no specific legislative language still drafted. But basically, the implication is that the definition is of historic Nicene Christianity. Which BTW means the Orthodox, Catholic, and mainstream Protestant churches dating to the Reformation are included.
That not following the major points of the Athanasian and Nicene (with or without Filiuoque) Creeds puts you outside the proper definition of Christianity and in the realm of heretics, is not a fringe extreme position, BTW, it has been the posture of the magisterium of the historic churches …well, since Nicaea.
Major components of LDS theology both official and popular are at odds with Nicene mainstream theology. IAIATheoligian but as I understand it the Big Issue at Nicaea was the nature of Jesus Christ Son of God and his place in the Trinity. To begin with, THE base foundational resolution is that the Godhead is one and eternal as the Trinity and that it is Topmost Tier heresy to deny the Trinity as defined in the founding Councils (you may argue on semantic details of the procedence of the Spirit, but not on that it’s three distinct homeostases/persons AND One single divine being/ouision, and if you can’t wrap your mind around that it’s your problem) ; that said then, the Creator Father is not an elevated mortal, the only human manifestation of the God is the incarnation, by the power of the Holy Spirit in Mary (NO heaveny consorts!) in the time of Augustus, of Jesus the Son who so happens, this Council finds and you better believe it or else, is fully truly God coequal and eternal, and truly fully human and this is no problem either.
Not in the creed but implicit in it is also that Jesus was never Adam or the Archangel Michael nor are scriptural references to Jehovah and Adonai Elohim addressing different characters, which various nontraditional splinters have argued as well.
Defining “historic Christianity” as that which follows the Nicene Council does not only exclude LDS but also the likes of Jehovah’s Witnesses, Christian Scientists, Oneness Pentecostals, Christadelphians, Swedenborgians, etc. Sure, some of those groups voluntarily withdraw from political participation, but for example it took a SCOTUS ruling to allow the JW’s to refrain from saying the Pledge of Allegiance so life could be made hard for them if Establishment of Religion were to return this way.