So, the question is about the most pressing issue in education...where to start?  The easiest place to begin is funding, of course; without money, schools are fundamentally unable to serve their students.  Without financial means, schools cannot provide the opportunities students need to succeed.  When a student is distracted by windows that do not close, by heating and air that do not work, by a lack of supplies and basic learning tools, those students are disadvantaged from the get-go.  It is easy to connect the majority of issues which currently confront the educational system to lack of funding.  It's a well known fact that American society under-funds education and has for years; education is usually the first place that budget cuts are directed towards, even in socially progressive states like California.  It goes to mention that in recent years, California directed some 80% of educational funding towards salaries and administration-- not students.