This thesis aims to investigate the high school expansion at Colégio Pedro II (CPII) along the 2000s, throughout the perspectives of the History of Present Time and the analysis of public educational policies, considering the concept of federalism, besides the impact of implementation arrangements. This research also investigates previous expansion cycles of CPII, besides the high school trajectory in this institution, regarding recurring educational reforms, since the 1970s. Therefore, we study the tactics and strategies which were applied to high school reforms, in addition to their resonance to the institution functioning and structure, we discuss CPII s planning and adaptations, considering their need to preserve its institutional program and aims - such as to be acknowledged for its tradition and teaching, once again, as an educational standard for Brazilian basic schooling. Nevertheless, we debate from Dictatorship period to Brazil s redemocratization, throughout the analysis of the relevance of associativism and the student s feeling of belonging to CPII, in uncertain moments on which the resistance and the fight for the institution took place to ensure - from legal mechanisms, as the Federal Constitution of 1988, to the streets – its remaining as a federal institution. Along the 1990 s, it is discussed the relevance of high school, as final step for the conclusion of basic schooling, besides the new challenges implied to the educational institutions. In the next decade, educational policies were designated to promote the interiorization and development of High School and the creation of Federal Institutions of Professional, Scientific and Technological Education (RFEPCT). In parallel to this context and amidst institutional redemocratization challenges, resources and structuring struggles, besides tensions surrounding the expansionist movement, three decentralized school units (UNEDs) of CPII were created: Realengo (2004), Niterói (2006) and Duque de Caxias (2007). Our methodology bases on documental analysis from different sources (such as pieces of news, official documents, institutional planning, among others) and Oral History remote interviews with school leaderships and public servants of CPII, who has experienced this 2000 expansion. We conclude that this expansion movement in the 2000s is comprehended as a tactic for institutional stability, once that Colégio Pedro II offers basic schooling, but it remains at federal level. This motivation encounters similarities upon previous expansion cycles. Furthermore, this movement takes place between tradition and innovation, as far as it denotes a period of ruptures and continuities: if, on the one hand, its extensive institutional program stands by at the new UNEDs for the preservation of the historical and traditional organicity of the school community; on the other hand, CPII presents innovations as affirmative policies at student selections, the creation of its Professional Master s Program in Basic Education, PROEJA, PRONATEC as well as its equivalation to federal institutes legislation (12.677/2012), assuming challenges and benefits from being integrated to RFEPCT. In conclusion, facing recurring educational reforms symbolizes more than its search for institutional stability and self-preservation, this is CPII s resistance.