How the Supreme Court's 'first gay justice' might be convinced to rule against same-sex marriage

One of the year's most dramatic cases will hit the Supreme Court on Tuesday when the justices hear a big fight over whether states have the right to ban same-sex marriage.

Gay marriage opponents will have their work cut out for them since Justice Anthony Kennedy, the key swing vote, is a gay rights hero who's even been dubbed the "first gay justice."

In order to successfully make their case to Kennedy, opponents of gay marriage will have to appeal to his love of states' rights.

"Opponents of same-sex marriage are hoping Justice Kennedy's love of states' rights overcomes his inclination towards protecting LGBT people," UCLA law professor Adam Winkler told me.

Kennedy's inclination to protect gay people spurred him to write the majority opinions for every big pro-gay rights ruling, including the opinion striking down the anti-gay Defense of Marriage Act and another striking down Texas's sodomy law.

One of former Kennedy's clerks, law professor Chris Walker, told me over email that he sees this next case "as the next chapter in Justice Kennedy's line of cases protecting gay rights."

This latest chapter will determine the constitutionality of gay marriage bans in Kentucky, Michigan, Ohio, and Tennessee, all of which were upheld by a federal appeals court.

One brief, filed on behalf of the state of Tennessee, quoted a previous opinion that Kennedy wrote noting that no one level of government has "complete jurisdiction over all the concerns of public life," as SCOTUSBlog noted.

This could be an appeal to Kennedy's history of promoting federalism. That history even includes Kennedy's 2013 decision striking down the Defense of Marriage Act, the US law that effectively deprived same-sex couples of federal benefits like Social Security benefits of deceased spouses. Kennedy's ruling touched on states' rights by noting that by "history and tradition the definition and regulation of marriage has been treated as being within the authority and realm of the separate states."

A ruling finding states can't ban gay marriage if they want to could contradict that DOMA ruling.

Kennedy, however, does not always favor states' rights over individual rights. When he struck down the state of Texas's sodomy ban, for example, he championed the rights of Texans over Texas.

"I think Justice Kennedy will say there is a fundamental constitutional right to marry," Winkler said, "and states do not have the authority to infringe on fundamental rights."