Protecting Marriage or Legislating Morality? Same-Sex Marriage Equality under the US Constitution

Perry v Schwarzenegger, Case No. C 09-2292 VRW (US District Court for the Northern District of California, 4 August 2010)

The US District Court has held that a prohibition against same-sex marriage violates the US constitutional requirements of ‘due process’ and equal ‘protection’.


Following an amendment to the California Constitution in November 2008, same-sex marriages could not be not recognised under California state law.  In May 2009, two same-sex couples were therefore denied Californian marriage licences by California authorities.

California voters had voted to amend the Constitution through a ballot proposition known as Proposition 8.  It followed an earlier attempt to amend state legislation in similar terms.  The earlier attempt, another ballot proposition known as Proposition 22 (or the ‘Defense of Marriage Act’), was invalidated by the California Supreme Court.  The Court had found that Proposition 22 violated the California Constitution’s equal protection guarantee (In re Marriage Cases).

Proposition 8 initially survived challenge in the California Supreme Court (Strauss v Horton).  Three days before that decision, the couples who had been denied marriage licences by Californian authorities filed suit in the US District Court, seeking a declaration that Proposition 8 was invalid, and an injunction against its enforcement.  They pleaded that Proposition 8 violated the Fourteenth Amendment of the United States Constitution.

While the suit named a number of government defendants (including California’s Governor, Arnold Schwarzenegger), the State’s Attorney-General conceded Proposition 8 was unconstitutional, and the remaining government defendants declined to defend the action.  Thus, it was left to Proposition 8’s proponents (led by a State Senator), who were granted leave to intervene as defendants, to defend the suit.


Violation of the Due Process Clause

The Due Process Clause, part of the Fourteenth Amendment to the US Constitution, provides that ‘[n]o State … shall .. deprive any person of life, liberty, or property, without due process of the law’.

It is ‘well established’ by Fourteenth Amendment jurisprudence that the freedom to marry is one of the fundamental rights protected by the Due Process Clause.  The defendants argued that this right was only available to opposite-sex couples, and that the plaintiffs were seeking recognition of a new right (ie same-sex marriage) that was not recognised by the Due Process Clause.

The Court disagreed, holding that the plaintiffs were seeking to exercise the same right that had been previously recognised, and that the state was obliged to allow them to do so under the Due Process Clause.

While marriage had not been ‘traditionally … open to same-sex couples’, the Court concluded that marriage ‘is a union of equals’ to which gender is irrelevant (and is therefore a right open to same-sex couples).  In particular, the Court noted that:

  • despite the defendants’ assertions that the ‘central purpose of marriage … [was] to promote naturally procreative sexual relationships’, the state had never inquired into procreative capacity or intent before issuing a marriage licence, and marriage was ‘more than a licence to have procreative sexual intercourse’ (with ‘choice and privacy’ also pivotal);
  • race and gender restrictions that had previously shaped marriage (including coverture and anti-miscegenation laws) were never part of the ‘historical core’ of marriage; and
  • California had eliminated marital obligations based on gender, and same-sex and opposite-sex couples were equally able to perform the rights and obligations of marriage.

Same-sex couples had the ability to enter into registered partnerships under California law, but this was not enough to satisfy the state’s obligations under the Due Process Clause.  Although the Court noted that domestic partnerships offered ‘almost all of the rights and responsibilities associated with marriage’:

  • domestic partnerships existed solely to differentiate same-sex unions from marriages; and
  • marriage was a ‘culturally superior status compared to a domestic partnership’, and withholding the designation of marriage ‘significantly disadvantaged’ the plaintiffs.

On the defendants’ ‘minimal evidentiary presentation’, Proposition 8 could not withstand strict scrutiny.  It therefore violated the Due Process Clause.

Violation of the Equal Protection Clause

The Equal Protection Clause, also part of the Fourteenth Amendment to the US Constitution, provides that no state shall ‘deny to any person within its jurisdiction the equal protection of the laws’.

The Court found that Proposition 8 discriminated on the basis of sexual orientation (by ‘targeting gays and lesbians in a manner specific to their sexual orientation and because of their relationship to one another’).  Classifications based on sexual orientation are subject to strict scrutiny.

However, strict scrutiny was not required because, even applying a ‘rational basis’ review (a lower standard of review), Proposition 8 failed, and therefore violated the Equal Protection Clause.

The defendants had argued that there were six relevant state interests justifying Proposition 8, each of which the Court rejected:

Alleged interest Court’s reasoning
Preservation of the traditional institution of marriage as the union of a man and a woman Tradition alone cannot form a rational basis for a law, does not rationally further a state interest; rather, it harms the state’s interest in equality.
Proceeding with caution when implementing ‘radical’ changes to a ‘bedrock social institution’ Same-sex marriage has no adverse effects on society or the institution of marriage.  The evidence showed ‘beyond debate’ that allowing same-sex couples to marry had a neutral ‘if not positive’ effect and ‘would benefit the state’.  The defendants’ contrary evidence was not credible.
Promoting opposite-sex parenting over same-sex parenting The evidence showed ‘beyond any doubt that parents’ genders are irrelevant to children’s developmental outcomes’.  Proposition 8 had nothing to do with children, because it ‘simply prevents same-sex couples from marrying’.  Same-sex couples with children were treated identically to opposite-sex parents under California law.
Protecting the freedom of those who oppose same-sex marriage Proposition 8 did not affect the rights of those opposed to homosexuality or to same-sex marriage, and individuals’ moral views were an insufficient basis to enact a legislative classification.
Treating same-sex couples differently from opposite-sex couples Under California law, for all relevant purposes, same-sex and opposite-sex unions are the same.  Only moral and religious views form the basis for the contrary belief.
Any other conceivable legitimate interests identified during the proceedings Many of the purported interests identified were ‘nothing more than a fear or unarticulated dislike of same-sex couples’, and on the evidence, Proposition 8 ‘simply conflicts with the guarantees of the Fourteenth Amendment’.

The Court reasoned by inference from the evidence that the ‘sole premise’ for Proposition 8 was the ‘private moral view’ that same-sex couples are inferior to opposite-sex couples.  Again, this provided no proper basis for the state to legislate.

Relevance to the Victorian Charter

It is widely expected that the decision will be appealed, ultimately to the United States Supreme Court.  A running theme through the trial judge’s decision is that the defendants’ case was wholly unsupported by the evidence it led.  The majority of the defendants’ witnesses were not called to give evidence, and their two experts were criticised by the trial judge for their lack of credibility and reliability; the trial judge decided that little or (for one of the experts) ‘essentially no weight’ should be given to their opinions.  In contrast, the trial judge found the plaintiffs’ experts were ‘amply qualified’ and offered credible opinions.  This is expected to influence the disposition of any appeal.   

Like the United States Constitution, the Victorian Charter recognises that every person has the right to enjoy their human rights ‘without discrimination’ (s 8(2)), and is entitled to the ‘equal protection of the law’ (s 8(3)).  The decision (and any subsequent appellate reasons) may be persuasive in interpreting the scope and content of the ‘equal protection’ guarantee under the Victorian Charter.  Of course, it is important to recognise that the Victorian Charter imposes a different test to the ‘strict scrutiny’ and ‘rational basis’ tests for limiting the rights to due process and equal protection propounded in Perry.  Under the Victorian Charter, ‘reasonable limits … demonstrably justified in a free and democratic society’ may be applied to human rights (s 7(2)).

In the context of the same-sex marriage debate in Australia, the decision will have no immediate legal impact.  The Commonwealth Marriage Act 1961 reserves marriage to opposite-sex couples, and any inconsistent state law would be rendered invalid by virtue of s 109 of the Australian Constitution.

The decision is available at

Samuel Porter, Solicitor, Mallesons Stephen Jaques Human Rights Law Group