The COVID-19 pandemic hit Brazil in a moment of serious political crisis: after the election of a populist leader, with authoritarian tendencies. Such authority responded to the pandemic by denying its seriousness and adopting measures which gave rise to important limitations on fundamental rights. The paper demonstrates that the protection of democracy, fundamental rights, and the fight against the pandemic, in Brazil, have been performed by the integrated work of institutional watchdogs, such as the legislative branch, the Brazilian Supreme Court and the states of the federation. It will also demonstrate that this defense was based on common international standards on the matter (“ius constitutionale comune”). Although the country's sanitary situation is critical, the case demonstrates that: (i) the cooperative work of institutional watchdogs and (ii) the guidance of common international standards can be powerful tools for the protection of democracy and fundamental rights.