A TFA alum on the biggest challenge teaching in an urban school Much of the education debate is framed around the unions, tenure and teacher quality, but I can't imagine anyone succeeding in a teaching environment like the one described here.http://www.anurbanteacherseducation.com/2011/02/tfa-alumnus-describes-barriers-to.html I'm sympathetic to the argument about our need to reform rules around seniority, but the problem is obviously many layers more complex.