Editor’s note: This Q&A was written by both Madalena Monteiro from Liberty Legal and André Miranda from Fieldfisher.

They will also co-host a webinar diving deeper into these topics on February 26.

What did the Constitutional Court judgement actually say?

The Constitutional Court declared the following four provisions unconstitutional and not fit to be promulgated in the form submitted:

  1. Article 6 (1) ( f) of the Nationality Law — the provision that would exclude naturalisation for anyone with a criminal conviction punishable by two years or more in prison. The Court held this automatic exclusion violated fundamental constitutional principles (including proportionality, equality and the prohibition on automatic penalty effects).
  2. The second part of Article 9 (1) (a) — this related to vague criteria for opposing the acquisition of nationality based on supposed lack of effective ties to the community and behaviour rejecting national institutions/symbols. The Court found this provision indeterminate and in conflict with constitutional requirements for clear legal norms, particularly where fundamental rights are concerned.
  3. Article 12‑B (3) — the rule excluding consolidation of nationality if obtained “manifestly fraudulently.” The Court held this provision conflicted with constitutional principles, including personalisation of sanctions and proportionality, because it could affect persons who acquired nationality in good faith.
  4. The norm extracted from the transition rules contained under Articles 7 (3) and 7 (4) of Decree no. 17/XVII — i.e., the rule that, for pending procedures, granting nationality would depend on whether requirements were met as of the date of application, and the attempt to characterise that rule as interpretative (so that it could have retroactive effect). The Court said this was not a genuine interpretative rule and, when applied to pending cases, violated the principle of protection of legitimate expectations.

These four norms were struck down because they conflicted with core constitutional principles, including proportionality and equality, legal certainty and clarity, legitimate expectations and protection against retroactive restrictions of rights and personalisation of sanctions (no automatic effects of criminal convictions).

The Court did not pronounce these provisions unconstitutional, meaning they remain valid unless later successfully challenged in a concrete case to be scrutinized by the Court:

  1. The provision requiring stateless persons to have legally resided in Portugal for at least four years in order to be eligible for naturalization was subject to the Court scrutiny. It was noted that this provision does not include the corresponding procedure for recognizing statelessness, which could potentially amount to an unconstitutionality by omission. However, omissions cannot be assessed within the scope of the constitutionality review requested by the Socialist Party.
  2. The revocation of the provision regarding the calculation of the period of legal residence (starting on the date of submission) which was accepted by the Court based on the fact that it was an exceptional rule, lawmakers have the discretion to adjust legislation, the principle of legal certainty does not guarantee immutability of legal regimes but requires predictability, and there was some predictability regarding this change.
  3. The absence of minimum transitional regime was considered not unconstitutional despite solid reasoning evidenced by the Socialist Party that the proposed changes would frustrate expectations of individuals who planned their lives under the old law and who faced serious delays beyond their control in the processing of their applications.
  4. Changes to the residence requirement (e.g., extending residence periods like the move to ten years for many non‑EU nationals)  were not listed in the constitutional review request submitted by the Socialist Party, so they were not subject to the Court´s ruling.

What did the court say about legitimate expectations (e.g. section D.7 of the ruling)?

In section D.7, the Constitutional Court focuses on how the legislator tried to deal with the temporal application of the law through Article 7 paragraphs 3 and 4 of Decree No. 17/XVII, which stated the following (we highlighted the modification proposed):

Article 7

Temporal Application

1 – This law shall take effect as from the date of its entry into force, without prejudice to the provisions set out in the following paragraphs.

2 – Administrative procedures pending on the date of entry into force of this law shall be governed by Law No. 37/81 of 3 October, in the version in force prior to this law.

3 – The approval of applications for attribution or acquisition referred to in the preceding paragraph depends on the fulfillment, at the date of their submission, of the requirements set out in Law No. 37/81 of 3 October, in the version in force prior to this law.

4 – The provision set out in the preceding paragraph shall be of an interpretative nature.

On the one hand, by stating that, in pending procedures, approval now depends on the requirements being met “as of the date the application is filed”; on the other, by labelling that rule as “interpretative”, so that it would be treated as forming part of the previous regime, thus with a retroactive effect, and would therefore take effect also in relation to proceedings already initiated. The Court rejects this characterisation. It explains that a genuinely interpretative statute makes sense only where the prior law was uncertain or genuinely disputed, and the new provision merely fixes a solution that courts could have adopted.

Here, that is not the case, because the previous regime was not uncertain and, moreover, the new solution does not reflect a plausible interpretation of the law then in force. Rather, it changes its meaning by shifting the relevant moment for verifying the requirements from the decision to the application.

For that reason, the Court considers that this is an innovative rule which, if applied to pending cases, produces retroactive effects in an intermediate sense (retroactivity of “ongoing situations”), because it redefines the legal framework applicable to legal situations that have already begun and are still “in formation”. This characterisation matters because it leads the Court to reject a direct breach of Article 18 (3) of the Constitution (which, in the Court’s case law, mainly targets “strong” retroactivity), but it opens the door to constitutional review under the principle of protection of legitimate expectations, inherent in Article 2 of the Constitution. And it is precisely there that the decisive criticism lies: for someone who filed an application under the previous regime, it is reasonable to expect that the procedure already initiated will be decided under that regime, including the idea, which is recognized in the administrative case law cited in the judgment, that, in certain naturalization situations, requirements that were not fully satisfied at the time of filing may become satisfied while the procedure is pending and can therefore allow approval at the time of the decision.

The Court stresses that acquiring citizenship is a life‑shaping decision, clearly a fundamental right subject to Constitutional protection, and that if the legislator wishes to impose a change that affects pending applications, it must provide concrete public‑interest reasons to justify the frustration of those expectations; since it did not, the Court concludes that the sacrifice imposed on applicants is excessive and disproportionate, and therefore the application of that rule to pending procedures violates the principle of protection of legitimate expectations (Article 2).

Is it possible to file a citizenship application early and be covered by the existing rules?

As for the practical question of whether people who have not yet met all requirements can file a citizenship application before the new law takes effect and still be “covered” by the current rules (for example, by applying before reaching the five‑year threshold), what can be drawn from D.7 is more nuanced than a blanket “yes”. The judgment strengthens the idea that there is a constitutionally relevant expectation when someone files under a legal framework which, under the law then in force and its established judicial/administrative interpretation, allows certain requirements to be completed during the pendency of the procedure and assessed at the time of the decision. In those cases, there is a genuine legal basis to trust that the case will be decided according to the logic of the regime in force when it was initiated, and it is exactly that trust that the Court protects against being retroactively “cut off” through a purported interpretative rule.

But the judgment does not say (nor does it imply) that any “premature” or strategically early filing, without support in the applicable rules, automatically guarantees application of the former regime. The protection arises from legitimate and well‑founded expectations grounded in the applicable law and how it was being applied, not from a simple rush to file regardless of the legal admissibility of the application or the substantive prerequisites of the claimed right. 

In practical terms, therefore, the safest reading of D.7 in our opinion is: current rules may still apply to applications filed before the new law, even if some requirements are only met by the time of the decision, if (and to the extent that) that possibility follows from the regime in force and its application/case law. However, D.7 alone does not support the proposition that filing before completing five years of residence will always be sufficient to “lock in” the old regime, because that will depend on whether the current legal system actually permits that requirement to be completed and assessed at decision stage, and on whether the application is not legally untenable from the outset.

In D.7 the Constitutional Court is essentially dealing with a constitutional “limits on retrospetive change” problem, not with a general rule that any earlier filing automatically secures the old regime. 

The Court’s reasoning is conservative in this sense: it objects to the legislator trying to apply, to pending procedures, a new rule that shifts the relevant moment for verifying requirements to the date of application while calling that shift “interpretative.” The Court says that the label is not credible where the previous law was not uncertain or genuinely controversial and the new rule is, in substance, an innovation. In that setting, applying the new timing rule to pending cases would be retrospective and must be tested against the protection of legitimate expectations (Article 2 of the Constitution). The Court then finds a violation because applicants who filed under the prior framework could reasonably expect their pending procedure to be decided within that framework and because the legislator offered no specific public‑interest justification for frustrating those expectations in pending cases.

From that, a cautious practical takeaway is the following: D.7 strengthens the argument that genuinely pending applications should not be disadvantaged by a later attempt to retroactively change the applicable timing rule, especially where the existing regime and its established application allow relevant conditions to be assessed at the time of the decision. However, D.7 does not itself confirm that filing before all substantive requirements are met is always permissible or effective, and it does not establish that an applicant can invariably “lock in” the old rules simply by submitting an application early. Whether an application filed before reaching a five‑year residence threshold is covered by the current rules will still depend on how the existing legal framework treats that requirement (for example, whether it is a condition that must already be satisfied at filing, or whether it may lawfully be satisfied during the pendency and assessed at decision stage), and on whether the application is legally viable as a properly constituted procedure from the outset.

What is the expected process going forward?

After the Constitutional Court’s preventive review decision on the nationality law amendments, the next steps are essentially legislative and political rather than judicial. After the Court found that a number of provisions in the proposed amendments were unconstitutional, President Marcelo Rebelo de Sousa formally vetoed the nationality law decrees and returned them to the Assembly of the Republic. Until Parliament reactivates the legislative process, approves a new decree (which cannot go against the ruling of the Court), and the President promulgates it, the existing Nationality Law remains in force and the drafted amendments do not apply.

Politically, the governing majority (led by the PSD with support from allied parties) now faces a choice about when and how to resubmit a revised legislative proposal. The Government and its supporting parties in Parliament might decide to delay re‑submission of a revised nationality law until after the recently elected President formally takes office on 9 March 2026, particularly if they perceive that the new President might be more receptive to a constitutionally robust version of the reform or to reduce political friction around a contentious social policy. However, there is no constitutional requirement to wait for the new President. Parliament can revise and adopt a new text at any time, subject to ordinary legislative procedure. However, in our opinion, it is unlikely that any action is made before President António José Seguro takes the office.

Once a revised law is passed by Parliament and sent to the President of the Republic, the President has several formal powers under the Constitution. The President may promulgate the law if he considers it constitutional, or he may exercise a political veto and return the law to Parliament with his reasons. Also, if the President has serious constitutional doubts about the revised text, he may also refer it to the Constitutional Court for a preventive review before promulgation, thereby prompting another judicial assessment of constitutionality. The grounds for such a veto or referral would generally be that specific provisions of the revised law may still be incompatible with constitutional principles (for example, the rule of law, legitimate expectations, legal certainty, equality before the law or other fundamental rights). If the President vetoes a law that has not been declared unconstitutional, Parliament may override the veto by re‑passing the law with a qualified majority under the Constitution (typically a two‑thirds majority, depending on the type of law), but that is a separate political process. Parliamentary groups also retain the option under Article 278 to initiate a preventive review themselves, for example, a group of at least one‑fifth of deputies can send the bill to the Constitutional Court even if the President does not do so, so long as the law is in organic law (a special category of laws), as it is the case of the nationality legal regime.

In short, the immediate process will involve Parliament reworking the draft to address the Court’s objections (but not limited to, since any political party can submit their own legislative proposal on the same matter) and then deciding when to present it to the President, and the new President may either promulgate, veto, or refer the text again on constitutional grounds.

What is the newly elected president’s stance on the Nationality Law?

António José Seguro has not publicly set out a detailed substantive position on the specific content of the nationality law reform, such as the proposed residence requirements or criminal record thresholds. His public general comments came in the context of the presidential campaign and have focused primarily on the legislative process and the importance of political consensus.

Mr. Seguro emphasised that laws of significant social sensitivity, such as nationality legislation, should be crafted with the broadest possible cross-party support. He criticised the parliamentary majority’s handling of the reform, arguing that excluding the Socialist Party from a consensus on such an important matter was a political mistake. In his view, nationality law should not bear an “ideological mark,” and reforms of this nature should reflect wide political agreement rather than partisan division.

Seguro also indicated that, as President, he would adopt a careful constitutional approach to the reform. He stated that he would scrutinise the nationality law to ensure full respect for constitutional norms. While this does not constitute a clear endorsement or rejection of specific provisions, it signals that he would prioritise constitutional compliance and broad political legitimacy in assessing the law.

More broadly, he framed the controversy over the nationality reform as symptomatic of a deeper problem of political polarisation. Rather than focusing exclusively on the legal substance of the reform, he characterised the process as politically flawed, arguing that sidelining key parties in the discussion of such a fundamental issue was unwise.

In practical terms, Seguro’s stance cannot be described as clearly “for” or “against” the specific content of the reform. His position centres on process, consensus, and constitutional respect. As President, he would have the authority to request a preventive constitutional review, veto and return the law to Parliament if he considered it constitutionally problematic or lacking sufficient legitimacy, or promulgate it if he judged it to be constitutionally sound and reasonably consensual.

His public remarks suggest that he would approach the matter cautiously, with particular attention to constitutional boundaries and the need for broad political agreement.