In Catholic canon law there is no concept of “revoking Catholic citizenship” in the civil/national sense. What canon law does have is (a) ways a baptized Catholic can lose certain canonical status and ecclesiastical participation, especially through grave canonical penalties like excommunication, and (b) a specifically defined notion of “formal defection from the Catholic Church” that can trigger particular legal effects where the Code of Canon Law refers to it.

Below are the principal canonical grounds that correspond to what people often mean by “revoking membership/canonical standing.”

Framework (what you’re really asking)

• Terminology: “Catholic citizenship” = canonical membership/status, not a civil passport.
• Gravest canonical grounds: apostasy, heresy, or schism can bring excommunication (a medicinal penalty).
• Formal/declared defection: “formal defection” requires internal decision + written external manifestation + reception by competent authority.
• Administrative effects: some consequences (e.g., removal from an ecclesiastical office) require an established fact via a competent declaration.

“Catholic citizenship” in canon law: canonical membership/status

Canonical effects are attached to being baptized and belonging to the Church. When the Church imposes a penalty such as excommunication, it is a serious medicinal censure that deprives the person of participation in ecclesiastical common blessings.

That is the closest canonical analogue to “revoking” a kind of standing—though even then, canon law does not treat baptism as simply “cancelled.” (The Church’s penalty is about canonical communion and participation, not extinguishing baptism.)

Apostasy, heresy, or schism: the clearest canonical “grounds”

Canon law specifies that:

What this means canonically

• “Latae sententiae” means the penalty is incurred ipso facto when the delict is committed (not merely after a sentence is imposed), unless law provides otherwise.
• Excommunication here is precisely the canonical penalty attached to those grave realities.

Limits (important nuance)

Even excommunication is described as medicinal and oriented toward correction and return, not merely “punishment for its own sake.”

So, apostasy/heresy/schism are the core grounds for the gravest canonical status consequence explicitly stated in your provided sources.

“Formal defection from the Catholic Church”: a stricter legal concept

Separately from “publicly defected” or “apostasy/heresy/schism,” the Church recognizes a juridical concept called actus formalis defectionis ab Ecclesia catholica (“formal act of defection”). The Dicastery’s 2006 communication explains that this concept is distinct from merely “virtual” abandonment deduced from behaviors, and that it has specific theological/juridical requirements.

Canonical requirements for a true formal act

The same 2006 text explains that for abandonment to be validly configured as a true actus formalis defectionis (so that the exceptions foreseen in the canons that refer to it would apply), there must concretely be:

• (a) an internal decision to leave the Catholic Church
• (b) the realization and external manifestation of that decision
• (c) reception of that decision by the competent ecclesiastical authority

And it further specifies a crucial juridical formality:

It concludes that:

What does not count as “formal defection”

The 2006 communication contrasts formal defection with other cases and emphasizes the need for the specified internal and formal external elements; it also treats the issue as requiring more than generalized “behaviors” or “virtual” abandonment.

“Public defect” and administrative effects (e.g., removal from office)

One of the clearest provided examples of an administrative consequence tied to defection is canon law on removal from an ecclesiastical office:

• A person who has “publicly defected from the Catholic faith or from the communion of the Church” is removed from ecclesiastical office by the law itself.
• But that removal “can be enforced only if it is established by the declaration of a competent authority.”

So, in practice, even where “public defection” is the ground, canon law still requires that the fact be established by competent declaration for enforcement of certain legal consequences.

Penal-law structure: how these grounds operate

The Code also clarifies the general framework of penalties:

• Penalties are generally ferendae sententiae (incurred after imposition), but where the law expressly establishes latae sententiae, the penalty binds ipso facto upon commission.
• The Code treats excommunication as one of the most serious medicinal penalties, and your sources explicitly link excommunication to apostasy/heresy/schism.

Bottom line

If “revoking Catholic citizenship” is meant as removing canonical standing/communion, the canonical grounds in your sources boil down to:

• Apostasy, heresy, or schism → latae sententiae excommunication.
• Formal defection requires a specific legal configuration: internal decision + written external manifestation before the competent authority + reception by that authority.
• Some administrative consequences (e.g., removal from ecclesiastical office for “public defection”) require the fact to be established by a competent declaration.

These are the core canonical grounds your provided texts support for what many people describe informally as “revoking Catholic standing.”