As a former teacher, I must tell you, that they are much more liberal in general than their friends and neighbors. Most have become teachers by getting degrees in education. It is, by and large, an inferior schools and basically they are being trained to conform to the dominant mind-set of the schools. Not to say that there is not a significant minority who differ, but they have little influence in the “profession.” Progressive education is more than just a name. If you want to know why increased spending produces so little result, you need to know that the same ideas keep getting recycled in public education with new labels. Ultlmately they derive from those of John Dewey, for whom the schools were an instrument for instilling “democratic thought” in the students. Dewey was also a political liberal and a founder of the AFT.
I know all that as well, I think you might be on the wrong thread to talk about education and where it went wrong.