The Obama administration on Thursday filed a brief with the Supreme Court urging it to strike down a gay-marriage ban in California, which was passed by the Golden State's voters in a 2008 referendum known as Proposition 8. The administration argues that the ban violates the Constitution's equal protection clause, in the far-reaching brief that suggests similar laws in other states are also unconstitutional in the administration's view. In a statement, Attorney General Eric Holder said the government "seeks to vindicate the defining constitutional ideal of equal treatment under the law." Here, four takeaways from the latest round in the battle for gay rights:

1. This is a sweeping defense of gay marriage
The brief constitutes the administration's strongest defense yet of same-sex marriage, arguing that the equal protection clause forbids California from offering civil unions to gay couples while denying them the right to marry. In addition, the brief says bans on gay marriage must meet a rigorous test known as "heightened scrutiny" — meaning states must prove that the bans are "substantially related to an important government objective." The brief technically does not address laws in other states, but if the court were to agree with the administration's rationale, it's believed that "no state could, under constitutional guarantees against discrimination, deny same sex couples the right to marry," writes Pete Williams at NBC News.

2. Obama seems to have changed his position on gay marriage
In 2012, Obama became the first sitting president to endorse gay marriage, though he insisted that it was up for individual states to decide. The administration's brief to the court, however, seeks to overturn a state constitutional amendment that was approved by voters. Obama appears to now believe that a state law explicitly barring same-sex marriages is irreconcilable with the equal rights afforded by the Constitution, which is the legal version of what he expressed at his inauguration: "Our journey is not complete until our gay brothers and sisters are treated like anyone else under the law," Obama said that day. "For if we are truly created equal, then surely the love we commit to one another must be equal as well." The shift is sure to draw criticism from small-government conservatives.

3. This is just one of two gay marriage cases before the court
In addition to the California case (Hollingsworth v. Perry), the Supreme Court this term will rule on a challenge to the Defense of Marriage Act (United States v. Windsor), which defines marriage as a union between a man and a woman. The Obama administration has taken a similar position in the latter case, but its implications are narrower. "The Supreme Court's ruling in the Defense of Marriage Act case will at most decide whether the federal government can discriminate against same-sex couples even if they married in states that allow such unions," say John Scwartz and Adam Liptak at The New York Times.

4. It remains unclear how the court will rule
The Supreme Court could possibly rule on narrow grounds, skirting the constitutional argument almost entirely. Proposition 8 came in response to a California court ruling legalizing same-sex marriage, and the justices could hold "only that voters cannot take away a right previously enjoyed, however briefly, by Californians," say Richard Wolf and David Jackson at USA Today. However, Obama's far-reaching argument may invite the court to respond with equal magnitude. In the past, the court's conservatives have expressed reservations about moving too fast on gay marriage, given that it is still not legal in the vast majority of states. Liberals, however, are hopeful for a decision that matches the scope of the administration's brief. Obama's sweeping argument "makes it more likely that the Supreme Court will strike down" Proposition 8, says Greg Sargent at The Washington Post.