Article "Dinamika kriminalisasi perkawinan berhalangan dalam Pasal 402 UU No.1 Tahun 2023" (Badilag Mahkamah Agung) explains: "Ketentuan dalam Pasal 402 ayat (1) dan (2) mengatur bahwa seseorang dapat dipidana apabila melakukan perkawinan padahal mengetahui adanya penghalang perkawinan yang sah menurut hukum, termasuk masih terikat dalam perkawinan sebelumnya tanpa izin yang sah." It further states that in Indonesia, the practice of polygamy without permission is responded to through criminalization in Law No. 1 of 2023 on the Criminal Code, and that Articles 402 and 403 provide a firmer legal basis by criminalizing polygamy without permission and concealment of marital status.

Article 402 of Law No. 1 of 2023 on the Criminal Code (KUHP baru) criminalizes "cohabitation as husband and wife with more than one person at the same time" when it is not registered according to the laws on marriage registration. The provision targets unregistered polygamous relationships by imposing criminal sanctions on individuals who live as husband and wife with multiple partners without fulfilling the administrative requirements of registration under marriage law. This norm has been criticized in academic and practitioner circles as expanding criminal law into areas that were previously governed by civil and administrative sanctions, raising questions about its consistency with the principle of mens rea and the notion that criminal law should be an ultimum remedium (last resort).

The Badilag Mahkamah Agung analytical article on Article 402 notes: "Pasal ini sering dinarasikan sebagai instrumen kriminalisasi terhadap praktik nikah siri atau poligami liar yang secara fikih mungkin sah namun cacat administrasi negara." It describes Article 402 as a manifestation of an "asas monogami terbuka" aimed at protecting legal order and the rights of women and children, and emphasizes that the article has dual dimensions: criminal (including the elements of the offense and mens rea) and family protection, limited by complaint-based mechanisms (delik aduan).

Article 402 of Law No. 1 of 2023 on the Criminal Code states: "Every man who, while already bound by marriage, enters into another marriage and does not register it with the authorized official, shall be punished…" (translation from Indonesian). The provision criminalizes entering into a second marriage without registration, focusing on the formal status of the marriage rather than harm to a spouse or others.

The Al-Zayn: Jurnal Ilmu article (2026) discusses the new Criminal Code: "Kemudian dalam KUHP baru yaitu pasal 402 UU No. 1 Thun 2023 yang berlaku 3 tahun sejak tanggal diundangkan yaitu tahun 2026, poligami tanpa izin pengadilan, sedangkan yang menjadi tindak kejahatan dari perilaku ini ialah perbuatan poligami yang tidak tercatat atau biasa disebut dengan poligami siri." It adds that without a court decision, polygamous marriages can be punished under criminal and civil (administrative) law, and notes that this reflects a mindset that considers polygamy as illegal and punishable by fines or imprisonment when done without proper legal procedures.

In Indonesian criminal law, the principle of mens rea emphasizes the importance of the mental condition of the perpetrator in determining criminal liability. A person cannot be subjected to criminal sanctions unless it can be proven that they had a certain intention or awareness related to the act. Mens rea is a fundamental aspect that determines whether an offender can be held criminally responsible for his actions; an act is complete as a criminal offense not only because of the physical act (actus reus), but also because of the presence of intention or awareness of the perpetrator.[1]

The basic criminal law maxim "Actus non facit reum nisi mens sit rea" affirms that an act does not make a person guilty unless there is a guilty mind. Mens rea, which simply means "evil intent", refers to the mental state of the perpetrator at the time of the criminal act. This concept requires the existence of intention or awareness of wrongdoing in order to punish someone. In practice this means that a person cannot be punished merely because of the act, but must also have a blameworthy mental state.[2]

Ultimum remedium is an established principle in Indonesian criminal law which says that criminal law must be made the last effort in law enforcement. This means that if a case can be resolved through other avenues such as family, negotiation, mediation, civil or administrative law, those avenues should first be taken. The article notes that ultimum remedium functions as a benchmark in legislative processes for resisting criminalization or negotiating whether conduct should be criminalized, rather than a principle applied by police or prosecutors once a statute already exists. It characterizes criminal sanctions as a "weapon of last resort" in comparison with civil or administrative sanctions.

According to Prof. Sahetapy, a criminal act consists of two elements: actus reus and mens rea; an act must be underpinned by a guilty intention before the perpetrator can be punished. Prof. Mahfud MD similarly states that to be punished, a person must have a guilty intent or mens rea. These scholars consider the existence of mens rea as mandatory for punishing someone for committing a criminal act. If a deed does not contain mens rea, it is not a criminal act and the perpetrator cannot be punished.[4]

Mens rea is connected to the principle "Keine Strafe ohne Schuld"—no punishment without guilt. In Indonesia and Western countries generally, mens rea must be proven in judicial practice, because it affects whether an act can be qualified as a complete criminal offense in the context of criminal liability. The principle emphasizes that guilty intent (mens rea) and the prohibited act (actus reus) are two inseparable elements in the formation of a criminal offense; it is not enough to show only actus reus, there must also be proof of mens rea.[6]

Hukumonline’s piece "Bedah Pasal 402 KUHP Baru" reports that legal experts emphasize the religious and social context of polygamy when examining Article 402 of the new Criminal Code. One expert explains that in Islam polygamy is not an obligation but a permissibility that may only be carried out in emergency conditions and with strict requirements, and that the state has the authority to regulate its implementation to protect women and children and ensure legal certainty. The discussion frames Article 402 as an instrument for managing polygamy and unregistered marriages within a criminal-law framework, rather than banning religious doctrines.

Article 36 of the new National Criminal Code (KUHP Nasional) emphasizes the principle of no punishment without intention: "there is no crime without guilt". The provision reflects the mens rea principle in Indonesian criminal law, requiring that criminal responsibility be based on fault or culpability. Article 53 of the KUHP Nasional further stipulates that judges must prioritize justice in sentencing when assessing culpability and intention.[8]

Indonesian criminal law recognizes the principle of ultimum remedium which states that criminal law should be used as the last alternative for punishing a criminal act. Ultimum remedium requires that other non-penal sanctions such as compensation, fines, warnings or other measures be attempted first before criminal law is used. Quoting Prodjodikoro, the paper explains that norms in administrative and civil law must first be addressed with administrative or civil sanctions, and only when these are not sufficient to correct social imbalance should criminal sanctions be used as a final remedy (ultimum remedium). Thus, ultimum remedium serves as an alternative of last resort in imposing punishment for an act.

The doctrine of mens rea is based on the maxim actus non facit reum nisi mens sit rea, meaning "an act does not make a person guilty unless the mind is also guilty". The article explains that in criminal responsibility there must be an element of fault in the perpetrator. It is considered unacceptable to impose punishment on a person who violates a criminal provision if that person does not have fault. Thus mens rea is described as the foundation of criminal law and of imposing punishment.[7]

Ultimum remedium is a legal term commonly used and understood as the application of criminal sanctions as the ultimate (last) sanction in law enforcement. There is also a concept of the "ultimum remedium principle" which embodies this idea that criminal sanctions should be a last resort. The explanation clarifies that the principle is not codified in a specific article of the old Criminal Code but is recognized doctrinally in Indonesian criminal law and is often invoked in discussions on whether to criminalize certain conduct or rely instead on administrative or civil measures.

Hengko Neldo, SH explains that mens rea in criminal law is the evil intention of the perpetrator of a crime. It derives from the criminal law maxim "actus non facit reum nisi mens sit rea"—an act does not make a person guilty unless done with evil intent. From this understanding, in a criminal offense it must be proven that there is an outward act (actus reus) as the manifestation of the will, and the mental condition or bad faith underlying the act (mens rea).[5]

This 2025 study examines the theoretical concept and philosophical foundation of the ultimum remedium principle and evaluates its application in criminalization policy in Indonesia. It finds that, in practice, many recent statutes have started to position criminal law not strictly as an ultimum remedium but sometimes as a primum remedium, especially in regulatory areas where administrative sanctions exist but are supplemented by criminal penalties. The article discusses how the shift from ultimum to primum remedium in criminalization can raise issues of over-criminalization and tension with basic criminal law principles, particularly when the criminal norm targets non-harmful administrative non-compliance rather than culpable conduct with clear mens rea.

In the context of ultimum remedium, the characteristics of criminal law mean that the arrangement of criminal sanctions is positioned as a last sanction. This implies that sanctions are prioritized through other mechanisms before criminal sanctions are imposed. The text notes that enforcement of criminal law in certain environmental statutes still takes into account the ultimum remedium principle by requiring administrative law enforcement first, and only when this is deemed unsuccessful are criminal sanctions used. It contrasts this with situations where primum remedium applies, meaning criminal law is used as a first resort when no other alternatives exist, such as terrorism cases.

Habiburokhman emphasised that the new Criminal Code does not prohibit nikah siri or polygamy. Articles 402 and 403 only regulate the prohibition of marriage when there is a lawful impediment according to the Marriage Law.[6] He stated that this provision is not a new norm, but is an adoption of former Article 279 of the old Criminal Code.[6]

An Instagram legal explainer summarises Article 402: "KUHP baru tidak melarang poligami, tetapi mensyaratkan adanya Izin Poligami dari Pengadilan Agama. Jika seseorang menikah lagi tanpa izin resmi (poligami liar/siri), ia dapat dijerat Pasal 402 karena dianggap melanggar halangan sah perkawinan yang diatur dalam hukum perdata Islam." It further explains: "Melakukan perkawinan padahal tahu ada 'halangan sah' (misalnya masih terikat pernikahan lain atau hubungan darah yang dilarang) bisa dipidana."

Article 402 of the new Criminal Code regulates the threat of imprisonment up to 4 years 6 months or a fine of up to category IV for a person who conducts a marriage knowing there is a lawful impediment (for example, certain conditions that prohibit marriage or the existence of another binding marriage).[10] Legal experts in this discussion stressed that marriage must be placed as an act of worship protected by the constitution, and the regulation aims to ensure legal order rather than to abolish religious marriages.[10]

Several Indonesian legal scholars have criticized provisions such as Article 402 of the new KUHP, which criminalize unregistered polygamy, as examples of "overcriminalization" and departure from the ultimum remedium principle. They argue that these norms punish status or formal non-compliance rather than clearly culpable harmful conduct, and therefore risk weakening the traditional mens rea-based foundation of Indonesian criminal law.

Ultimum remedium in criminal law means that if a matter can be pursued through other channels such as civil law or administrative law, those channels should be used first. Only when these avenues are inadequate should criminal sanctions be applied. The article from the Judicial Commission’s journal explores the application of ultimum remedium in Indonesian criminal policy and notes concerns that excessive criminalization of minor or administrative violations may violate the spirit of this principle, which is to limit criminal law to truly necessary and culpable cases.

Another Instagram post on the new Criminal Code states: "KUHP Baru (UU No. 1 Tahun 2023) tidak melarang poligami secara mutlak. Namun, seseorang dapat dipidana jika menikah lagi tanpa izin pengadilan atau tanpa persetujuan pasangan sah. Pasal 402–403 KUHP: Ancaman pidana penjara hingga 4,5–6 tahun." It notes that the permissibility of polygamy is regulated in Law No. 1 of 1974 on Marriage, which allows polygamy only under certain conditions and through a legal process.

Kompas TV reports a statement by Selly Andriany Gantina, member of Commission VIII of the DPR: she "menegaskan bahwa Pasal 402 Undang-Undang Nomor 1 Tahun 2023 tentang KUHP tidak dimaksudkan sebagai upaya negara untuk mengkriminalisasi ajaran agama, melainkan sebagai instrumen hukum untuk melindungi perempuan dan anak dari praktik nikah siri tanpa restu pasangan sah." She highlights that the provision focuses on legal certainty and protection for vulnerable parties rather than religious doctrine.

In a video reel, Selly Andriany Gantina explains that Article 402 of Law No. 1 of 2023 "mengatur pidana bagi pelaku nikah siri tanpa restu pasangan sah" and stresses that the provision is not an attempt to criminalize religious teachings but a legal instrument to protect women and children from socially and legally harmful practices. She notes that without formal registration, women and children often struggle to access basic rights and social security, and that marriage registration is crucial for state protection in cases like abandonment, domestic violence, and inheritance disputes.

The new Criminal Code regulates a prohibition on marriage with a party who is still bound in a lawful marriage. This rule is contained in Articles 402 and 403, which in principle prohibit a person from marrying the spouse of another person who is still legally bound by marriage, with the threat of imprisonment or a fine.[7] These articles do not prohibit nikah siri or polygamy; what is prohibited is conducting a marriage when there is a lawful impediment as defined by the Marriage Law.[7]

Based on Article 402 paragraph (1) of the new Criminal Code, a man who practices polygamy secretly or quietly without permission can be punished with imprisonment for a maximum of 4 years 6 months. The fine penalty can reach category IV.[9] The post explains that polygamy without official permission from the court falls under the scope of Article 402 as performing a marriage despite a lawful impediment.[9]