I won't say your prediction is impossible, but I really don't think the left wants to go there. Justices tip their hands all the time in concurring and dissenting opinions.
The Establishment Clause provides that "Congress shall make no law respecting an establishment of religion." Amdt. 1."
"As a textual matter, this Clause probably prohibits Congress from establishing a national religion."
"But perhaps more importantly, the Clause made clear that Congress could not interfere with state establishments, notwithstanding any argument that could be made based on Congress' power under the Necessary and Proper Clause."
"Nothing in the text of the Clause suggests that it reaches any further." - Justice Thomas on Elk Grove v Newdow
Thomas also wrote, in that same opinion:
"-- the government cannot require a person to "declare his belief in God."
" -- We repeat and again reaffirm that neither a State nor the Federal Government can constitutionally force a person 'to profess a belief or disbelief in any religion' -- "
I also agree with his point that; -- "the Clause made clear that Congress could not interfere with" [existing] "state establishments, -- "
IE -- Those the original States had that supported the old Colonial religions.
Joe commented that:
Quite simply, the clause does not suggest that "new" establishments of state religions are prohibited, nor can you present any ruling or any source at all that suggest they do.
Joe, -- States are guaranteed & required to have a Republican Form of Government, which more than "suggests", -- it rules out sectarian forms. -- See Art IV Sec 4.
Thanks for linking to this thread Joe.
Perhaps it will lead others to read more about Thomas, who I believe may mature into the best conservative Justices the Court has ever had.