Natalie Bennett, the leader of the Green Party of England, recently suggested that her party is “open” to granting legal status to marriages or civil unions involving more than two people.

In a question-and-answer session with readers of PinkNews, which describes itself as “Europe’s largest gay news service,” Bennett said her party is “open to further conversation” on legal status for polyamorous relationships.

PinkNews reports that a reader asked Bennett:

At present those in a ‘trio’ (a three-way relationship) are denied marriage equality, and as a result face a considerable amount of legal discrimination.

As someone living with his two boyfriends in a stable long-term relationship, I would like to know what your stance is on polyamory rights. Is there room for Green support on group civil partnerships or marriages?

Bennett replied:

At present, we do not have a policy on civil partnerships involving more than two people.

We are, uniquely in this country, a party whose policies are developed and voted for by our members.

We have led the way on many issues related to the liberalisation of legal status in adult consenting relationships, and we are open to further conversation and consultation.

Bennett’s comments coincided with oral arguments regarding the constitutionality of same-sex marriage at the Supreme Court last month.

During oral arguments last month at the Supreme Court, Justice Samuel Alito expressed concern that permitting same-sex marriages would grant legal precedence for groups of three, four or more.

“A group consisting of two men and two women apply for a marriage license. Would there be any ground for denying them a license?” he asked.

“What would be the ground under the logic of the decision you would like us to hand down in this case? What would be the logic of denying them the same right?” Alito continued.

Ryan Anderson, the William E. Simon senior research fellow in religion and a free society at The Heritage Foundation, said that Alito is right to be concerned.

“If the Supreme Court say ‘marriage equality’ requires redefining marriage to include same-sex couples, on what basis could the Court deny ‘marriage equality’ to same-sex throuples? Or opposite-sex quartets?” asked Anderson.

He continued:

Because the way that we arrive at monogamy in western law and culture is that it’s one man and one woman who can unite in the marital act that can produce new life and every new life has one mother and one father. Marriage is about uniting these people into a stable family life.

But once the law says the male-female aspect of marriage is irrational and arbitrary and bigoted, what is magical about the number two? What is the principled reason for denying ‘marriage equality’ to threes and fours and more?