The purpose of this research is to analyze the finance sustainability framework, from its interpretation as a constitutional principle, as a criterion for the administration of justice, to the study of the background, implementation and vicissitudes in the context of the COVID 19 pandemic. The analyzed thesis allows to contribute to the discussion, which is generated from the tension between the economic constitution and legal certainty, to the extent that the emphasis of the principle of fiscal sustainability can be interpreted to the detriment of fundamental, economic and social rights, and, in general, against the constitutional guarantees protected by the Social State of Law.