These briefs argue that Utah's gay marriage ban, and others like it, violate the 14th Amendment, depriving Americans of their rights to due process and equal protection.
For the state: The Church of Jesus Christ Latter-day Saints, 21 Utah counties, the Eagle Forum, 10 states whose own same-sex marriage bans are under attack and several conservative think tanks.
The pro "traditional marriage" lobby has urged the high court to leave marriage regulation to the states, arguing that states have the right to define marriage as they see fit and that deviating from the long-standing man-woman view of marriage may be harmful to children and society at large.
The more than a dozen briefs will be read and considered by the nation's high court when deciding which if any same-sex marriage case to take in its upcoming session.
Meanwhile on Friday, advocates of opposite-sex marriage delivered a 6-foot-tall stack of 18,682 petitions to Gov. Gary Herbert.
The petitions, organized and submitted by the conservative Sutherland Institute, were signed by Utahns who want to "show their support for traditional marriage and to thank Gov. Herbert and Attorney General Sean Reyes for defending Utah's marriage laws all the way to the Supreme Court."
The impact these petitions will have is likely minimal, because Herbert and Reyes already have made their positions clear and continue to defend Utah's voter-approved ban on same-sex unions.
The Sutherland Institute and other conservative organizations have argued that same-sex marriage is harmful to children and that maintaining marriage laws that exclusively allow unions between one man and one woman is in a state's best interest.
Utah has used similar claims in its defense of Amendment 3, which was overturned by U.S. District Judge Robert J. Shelby's historic ruling in December.
But supporters of same-sex marriage argue this state concern is not enough to trump personal freedoms and what they see as the guarantees of the 14th Amendment.
In their amicus briefs filed Thursday, 15 states ask the Supreme Court to intervene in the patchwork state-by-state legalization that has been happening for a decade, which, according to the states, harms their residents and poses threats to their marriages when they travel out of state.
"Married same-sex couples and their families reside throughout the country, in States that do and do not honor their marriages. The variation in state law creates a significant divide among families," according to the brief. "For those couples that live in, move to, or even travel through States that do not recognize their marriages, their lives are more complicated (and often more costly), their legal status is uncertain, and their families are left vulnerable. The problems created by some States' unconstitutional refusal to either allow or recognize marriages between same-sex couples merit the Court's intervention."
The states whose attorneys general signed onto the brief have either legalized same-sex marriage or refused to fight a judge's decision to overturn a state ban, effectively legalizing gay and lesbian unions. They are California, Connecticut, Delaware, Hawaii, Illinois, Iowa, Maine, Maryland, Massachusetts, New Mexico, New York, Oregon, Pennsylvania, Vermont and Washington.
The brief filed on behalf of four gay-marriage organizations focused more on what they describe as emotional and daily hardships faced by the families of same-sex couples.
Of the 30 businesses that signed onto the third brief to the court, 16 are Fortune 500 companies and include a range of household names such as Ben & Jerry's, General Electric, Pfizer, eBay, Nike, Staples, Target, Viacom, Levi Strauss & Co, CBS and Amazon.
The companies say they filed the brief in support of their lesbian, gay, bisexual and transgender employees, who suffer unequal treatment in states where their marriages are not recognized or not allowed.
"We are forced to implement inconsistent policies in the various jurisdictions in which we operate, and the mandated discrimination underlying these policies violates our stated corporate policies," the brief states. "Our ability to grow and maintain our businesses by attracting and retaining the best talent is hindered. The patchwork of state laws applicable to same-sex marriage impairs thus our business interests and employer-employee relations."
In the year since the U.S. Supreme Court overturned key aspects of the federal Defense of Marriage Act, 22 federal courts across 16 states have ruled that bans on same-sex marriage are unconstitutional.
This week, a federal judge in Louisiana became the first to uphold such a law, ruling that these laws are not discriminatory and that a state's fundamental right to define marriage is paramount.
A division among courts increases the likelihood that the U.S. Supreme Court will take on the issue of same-sex marriage, though it is unclear which case the justices may choose.
In their brief in support of Utah, attorneys general from 10 states point to this landslide of litigation as reason for the high court to intercede.
"Every single State with traditional marriage laws has been hauled to court, often with multiple cases, sometimes in both state and federal courts," the brief states. "Is there a federal constitutional right to same-sex marriage? The answer to that question, as raised by this case, will directly impact the states' historical prerogative to define marriage. Without an answer from this court the often repetitive litigation across the nation will continue unabated."
Utah's 21 counties took a different approach, touching instead on the majority of Utahns who voted to pass Amendment 3 in 2004 and the state's deeply rooted ideas of what marriage is.
"There are powerful reasons why the people of Utah wisely and responsibly may choose to continue to allow only male-female marriages. That is the universal historic and overwhelming global norm," said the brief, written by Brigham Young University law professor Lynn D. Wardle. "Among the reasons why Utah rejects same-sex marriage is concern about the direct and collateral social consequences of redefining that core social institution."
Among those consequences, the counties list: "the phenomenon of increased rates of abortion and diminished, diluted social shared understanding of marriage and marital responsibilities."
The counties that declined to join this amicus petition are Davis, Grand, Piute, Salt Lake, Summit, Tooele, Wayne and Weber.
Several religious organizations, including the LDS Church and Catholic Church, urged the Supreme Court to uphold a state's right to disallow gay and lesbian couples to wed on the basis of tradition and religious freedom.
"Legal uncertainty is especially burdensome for religious organizations and religious believers increasingly confronted with thorny questions," the brief said. "Is their right to refrain from participating in, recognizing or facilitating marriages between persons of the same sex, contrary to their religious convictions, adequately shielded by the First Amendment and other legal protections? Or is further legislation needed to guard religious liberties in these and other sensitive areas?"
The nation's nine justices are on break until October, at which point they will consider requests from Utah, Virginia and Oklahoma, which have already been filed with the court. Other states, whose cases are working their way through the system, are also expected to file for certiorari before the justices issue a decision.