Lawyer Alex Ali Mendez Diaz represented three same-sex couples from the Mexican state of Oaxaca whom local authorities denied marriage licenses. (Photo courtesy of Alex Ali Mendez Diaz)

The 56-page decision cites two U.S. Supreme Court cases that specifically addressed race-based discrimination and segregation: Loving v. Virginia that found state bans on interracial marriages unconstitutional and Brown v. Board of Education that struck down laws that allowed separate public schools for black and white students.

“The historic disadvantages that homosexuals have suffered have been amply recognized and documented: public scorn, verbal abuse, discrimination in their places of employment and in the access of certain services, including their exclusion from certain aspects of public life,” the judges wrote. “In comparative law it has been argued that discrimination that homosexual couples have suffered when they are denied access to marriage is analogous with the discrimination suffered by interracial couples at another time.”

They further point out the U.S. Supreme Court said in Loving v. Virginia that restricting marriage on the basis of race is “incompatible” with the Equal Protection Clause under the 14th Amendment of the Constitution.

“In connection with this analogy, it can be said that the normative power of marriage is of little use if it does not give the possibility to marry the person that one chooses,” the judges wrote.

The court released its decision more than two months after the judges unanimously struck down the Oaxaca law that defined marriage as between a man and a woman.

Three couples tried to apply for marriage licenses in the state, but local authorities denied their applications. Lawyer Alex Alí Méndez Díaz filed lawsuits on behalf of two of the couples in Aug. 2011 and a third in Jan. 2012 who sought legal recourse — an “amparo” in the Mexican judicial system — to ensure local authorities would protect their constitutional rights.

The ruling also comes roughly six weeks before the U.S. Supreme Court will hear oral arguments in cases challenging the constitutionality of California’s Proposition 8 and the Defense of Marriage Act.

“They do it when in our country there is no previous rulings on the subject,” Méndez told the Washington Blade from Mexico City when asked whether it is common for Mexican Supreme Court judges to cite cases from other countries in their decisions. “These rulings are the first at the national level that support the topics in the way in which we had planned.”

Marriage debate continues throughout Latin America

Same-sex couples have been able to legally marry in the Mexican capital since 2010, and the Mexican Supreme Court has ruled other states must recognize gay marriages legally performed in Mexico City. Gays and lesbians have also married in Quintana Roo on the Yucatán Peninsula, while the state of Coahuila offers property and inheritance rights and other limited legal protections to same-sex couples.

The Uruguay House of Representatives in December overwhelmingly approved a bill that would allow gays and lesbians to tie the knot. Same-sex marriage advocates expect the measure will easily pass in the country’s Senate in April — President José Mujica has said he will sign it into law.

A Colombian Senate committee in December also approved a same-sex marriage bill. A court in the Brazilian state of São Paolo later that month ordered registries to begin offering marriage licenses to same-sex couples without a judge’s approval.

Argentina has allowed same-sex couples to marry since 2010, while Chilean President Sebastián Piñera in 2011 said he would introduce a bill that would allow gay men and lesbians to enter into civil unions. Same-sex couples would be allowed to tie the knot and adopt children in French Guiana under a proposal the French Senate is scheduled to begin debating on April 2.

The Inter-American Court of Human Rights in Feb. 2012 ruled in favor of lesbian Chilean Judge Karen Atala who lost custody of her three daughters to her ex-husband in 2005 because of her sexual orientation. Three gay couples from Chile who had been denied marriage licenses filed a lawsuit with the tribunal last September after the South American country’s Supreme Court ruled against them.

The Mexican Supreme Court cited the Atala case its decision that only applies to the three same-sex couples who had sought marriage licenses in Oaxaca.

“It just confirms that fighting for marriage equality on a federal level makes more sense and is becoming an increasingly global trend,” Enrique Torre Molina, an LGBT activist and blogger in Mexico City, told the Blade.

The Mexican Supreme Court on Wednesday is expected to formally announce its decision on whether the Oaxacan law that defines marriage as between a man and a woman is discriminatory. The judges will have to rule on an additional “amparo” from Oaxaca before gays and lesbians can legally tie the knot in the state.

“For there to be same-sex marriage throughout the country, if there is not a reform of the civil laws of each state, we will need five rulings in each one of the states that comprise the federation [of Mexico,]” Méndez noted.