Evolutionism
The National Academy of Sciences, which is heavily involved in producing science curricula for American public schools, is at the forefront of promoting the theory of evolution and the eliminating of creationism being taught.
According to a decision in a Pennsylvania school case, it was argued successfully that any attempt in challenging evolution on strictly science terms was still an attempt at teaching religion. And the state could not constitutionally be allowed to promote religion. No other scientific discipline or theory has such protection from being challenged.