To see but one example of why we can't trust local school boards to lead meaningful reform efforts, see this post from the National School Boards Association (NSBA). Regarding this recent Wall Street Journal article on No Child Left Behind's lack of "bite"* for failing schools, NSBA says:
If the system that judges school performance is innately flawed, should??we be rushing to sanction these "failing" schools or should we be rushing to fix the system? Until NCLB gets its diagnosis right, schools should not be forced to make radical changes that are disruptive to students and their learning environment.
Well, yes, NCLB surely labels some schools as "needing improvement" that are pretty decent, such as those that are succeeding for most of their students but not for kids with learning disabilities, or those that are not up to standards yet but are making big gains over time. But all evidence indicates that the vast majority of "failing" schools are just that, and we shouldn't waste any more time (or come up with any more excuses) before we intervene aggressively in them. NSBA's proposal is a prescription for paralysis. Which is fitting, because most local school boards have resisted real reform forever.
Update: *As Liam notes below, Washington, D.C.'s, school system is instituting real reform. And guess what? It reports to the mayor, not the school board. Hardly a coincidence.