As far as the world standard goes, American public education is near the top of the ladder. But, when you compare the education here to other first world countries, we fall way short. This is not to say that all public schooling institutions are of poor quality, though, because there are many public schools in America that do provide quality education. It is the schools in poor areas that really bring down the national average and make our public education seem like such a joke. The primary reason for these inequalities is varying funds.
Although the federal and state governments provide some money for the schools, the largest portion of funding comes from local tax collection. So, in areas where the large part of the population is of the low-income persuasion, which often occurs in areas of largely minorities, the schools reflect this fact with lower quality facilities, books, and even teachers. The ironic thing about schools in areas like these is that they never seem to get any better. The cycle is perpetuating- poor education, low-income jobs, little school funding, poor education and so on.
Not only that, no one seems to want to help these people. The common view is that those schools need to help themselves and throwing money at them would not solve the problem. It's a good thing that we don't treat everything like this, because if we did, our culture would become much more strongly stratified, keeping the poor poor and the rich rich. The truth is, if nothing is done about these poorly run schools, they will continue to suffer and provide poor education to our children for generations to come, giving the children in those areas a much harder struggle to succeed than most other American children.