I just realized there's an English Wikipedia article on this exact concept. It says:
The Spanish-language term desafuero refers to the process through which a government official's official immunity to criminal prosecution is removed.
Strictly speaking the term is incorrect, as fuero (from Latin "forum") refers to the freedom of speech protection enjoyed by members of Congress, but since this protection is frequently confused with the immunity against criminal prosecution of top executive branch officials, the term is commonly used by the public in this latter sense.
Another Wikipedia article talks about a famous desafuero case in Mexico. The Spanish Wikipedia article explains:
El desafuero es el acto jurídico mediante el cual a una persona aforada se le retiran sus privilegios.
So it sounds like desafuero is a technical legal/government term used in certain governments of Spanish-speaking countries, and its proper English translation is... "desafuero."