The authors propose the terms of the debate about the controversial and aporetic institution of the pardon, which has a difficult fit in the scheme of the democratic State based on the separation of powers. To this end, the study starts from the background and historical reasons for the prerogative of mercy and its regulations in comparative law, which allows us to understand the scope of the issue and the complex legal nature of an institution, the pardon, which is equates to forgiveness and that must be scrupulously delimited from amnesty --oblivion--. The most recent national practice serves as an example, in the authors' opinion, of the need to move towards a new Spanish transitional pardon law, which must become an exceptional and residual resource, in fact doomed to extinction. The work harshly criticizes the pardons in the case of the «Procés » --which are classified as fraud of the Constitution-- and includes a specific proposal of lege lata vel ferenda. [ABSTRACT FROM AUTHOR]