A defense against opposition to Portuguese nationality is the response submitted by the applicant when the Portuguese Public Prosecutor's Office initiates opposition proceedings against the granting of Portuguese nationality, usually in cases involving grandchildren, marriage, and stable union (or de facto union) applications.
The most common grounds for opposition are:
- Conviction for a crime punishable in Portugal with a prison sentence of three years or more.
- Connection to activities related to terrorism or a threat to national security.
- Lack of effective connection to the Portuguese community (in certain types of proceedings and according to the legislation applicable to the case).