A seven-judge Supreme Court has unanimously ruled the first marriage of a man living here with two wives whom he married in his native Lebanon is valid under Irish law.

While his second marriage is not valid here, it may have legal consequences and the court’s findings do not compel the State to deny all legal effect to polygamous marriages in all contexts, the court stressed.

This case was rooted in the immigration area and it “may be desirable” to have some regard to the reality of familial bonds, it said.

A marriage that is only “potentially” polygamous (where a man has one spouse but the relevant legal system would permit subsequent marriages) is capable of being recognised under Irish law and public policy does not require such a marriage should not be recognised because a man later contracts a second marriage, the court held.

Recognition of an “actually” polygamous marriage would be contrary to a fundamental constitutional principle – of equality – and therefore contrary to public policy, it ruled.

In finding the second marriage not valid under Irish law, it said the institution of polygamy is not contemplated by the Constitution and is contrary to principles of various international instruments. Giving legal recognition to such a structure would “give legal effect to discrimination and subordination in a relationship where the principle of equality should hold sway”.

Ms Justice Iseult O’Malley stressed her conclusions, with which the other judges agreed, were subject to the right of the Oireachtas to consider and legislate for issues of public policy “subject to, and in conformity with, the Constitution”.

Mr Justice Frank Clarke, in a concurring judgment focussing on public policy issues, said there was a “strong imperative” “urgent” attention be given to whether legislation should be enacted to address the issues raised.

The case, involving the court considering for the first time the legal consequences here of a polygamous marriage entered into in another country, has implications for such marriages and for family reunification of successful asylum seekers.

The State argued neither of the man’s marriages should be recognised and Irish public policy is opposed to attaching legal consequences here to polygamous marriages.

Ms Justice O’Malley said the Constitution and Irish public policy in this era “clearly envisage a marriage as being a union between two people, based on the principle of equality and mutual commitment”.

There is no bar to recognition of a marriage that is in fact monogamous where the only objection is the system of law under which the couple married would permit more than one marriage, she found.

It can be presumed a significant number of the estimated 60,000 Muslims living here were married under a law that permits polygamy, she said. It seemed most of those are living monogamously with not many instances of actually polygamous households and refusal to recognise what are de facto monogamous marriages could cause “distress, confusion and disruption” to a significant number of people living here.

Recognition should be afforded as of the date of inception of the man’s first marriage and should not be withdrawn in the event of a second or subsequent marriage by him, she held.

The man was entitled to a declaration his marriage to his first wife was valid as of the date of its inception, she ruled.

While taking the view the man’s second marriage is not valid under Irish law while his first marriage subsists, that did not necessarily mean such a marriage “can never have legal consequences here”.

Public policy, she said, changes over time. While the State appeared to have previously permitted refugees with more than one wife choose which wife they wanted to join them, and to have then treated that marriage as monogamous, that policy had changed in light of court judgments and applications received and the attitude now was neither wife would be admitted.

The State had conceded during the appeal a “more nuanced position” might be adopted concerning potentially polygamous marriages, she noted.

The now 64-year-old man, while living in Lebanon, married his first wife in 1975 and his second in 1988 and has children with both. Under Lebanese law, a man can have up to four wives.

He came here in 1998, got refugee status here in 2000 and in 2002 became an Irish citizen. Having got refugee status, he applied under family reunification provisions for his second wife to join him and she was permitted do so in 2001 with their children on the express basis she was his wife. She is now an Irish citizen.

After getting Irish citizenship in 2002, he applied to have his first wife also admitted here and took High Court proceedings after the Minister for Justice refused. His first wife came here in 2006 seeking asylum and was refused, but later got permission to remain.

After the High Court refused recognition of his first marriage, he appealed to the Supreme Court. Both wives supported the appeal.

Ms Justice O’Malley said, while the Attorney General had said it was unlikely any step would be taken now to remove the first wife from the State, the issue of her status was “clearly not moot”.

Public policy changes over time and she considered various factors should contribute to a decision made on public policy grounds, including obligations under EU and international law.