In America we have a silly belief, peddled by the corrupt teachers unions, that we need tons of money to educate children--that's why funding per students has risen so dramatically over the past 35 or so years. Meanwhile, performance has stayed flat.
I thought you wanted to keep this apolitical. First you have to show that most of the increase in US spending per pupil is due to teachers' unions, not to laws about special needs children, English as a second language, changing textbooks and curriculum all the time, reducing class size (presumably partly due to union desires/demands, partly not), and so on. If you're so goddam interested in the question, why don't you find out how teachers' salaries and benefits in Japan compare to US salaries and benefits?
I just think it's really reprehensible to say, on the one hand, that you want to do a dispassionate comparative sociological analysis, and then to write a sentence like that. Finland, by the way, has nearly 100% unionized teachers, according to Diane Ravitch. So now you have to compare their union to US unions.
"You people are all the same," and it really, really sucks.