The problems started after the efforts to eliminate God from the public schools. When Christianity gets kicked out and is replaced with atheism, is when something moves in to fill the vacuum, just as is happening in Europe and is starting to happen here.
And for that you can thank the ACLU and it's cohorts.
I would say that the problems started when the first government school opened in the mid-1800s. Instead of receiving an education that was thoroughly grounded in that child's specific religion, the government school children were fed a generic ( lukewarm) Protestantism that could be accepted by the majority of the voters.
Right there at the beginning, generic and lukewarm is a problem. ( We know what Christ does to the lukewarm.)
When government opened compulsory tuition-free government schools it created a very hostile business climate for the forms of education that had taught generations of citizens up to the mid-1800s: homeschools, private tutoring academies in the homes of teachers, Sunday schools, and private schools.
Then add to the toxic mix the fact that Utopian Progressives ( who were highly influenced by the Marxist philosophies of Europe) have always been in charge of teacher training and curriculum development. That government schools would move to more and more secularism was inevitable.
My grandmother ( born in 1894) was subjected to a government schooling that was essentially godless. Yes, there were a few minutes of prayer in the morning. Yes, her teachers were able to soften the effects of the godless secularism,..but..her government education even by the late 1800s and early 1900s was **secular**.
What our nation needs are private conservative schools that will totally integrate the child's Judeo Christian religious beliefs throughout the entire curriculum. Lukewarm and generic will not be enough to defeat Marxism or Islamofascism.