I examine the dynamics of implementing at-scale reforms to provide meaningful educational opportunities to disadvantaged students in Mexico. To effectively reduce social inequality and exclusion, education policies need a mix of system-wide and targeted efforts that are implemented at scale and sustained long enough to become institutionalized. The resiliency of those policies requires an elusive balance between system-wide and targeted efforts, alignment between federal and state initiatives, and supportive politics. However, the politics of implementing system-wide reforms are more contentious than those involving targeted efforts because they disrupt entrenched interests, making such efforts harder to sustain. Targeted policies, while easier to implement, reinforce the segregation of students into different educational tracks of varying quality.