Who reversed the Sixth Circuit's decision, paving the way for same-sex marriage to become legal in places like Ohio?
U.S. Supreme Court
Title: Same-sex marriage in the Seventh Circuit
Passage: On September 4, 2014 the Seventh Circuit Court of Appeals unanimously upheld district court rulings striking down same-sex marriage bans in Indiana, and Wisconsin, just nine days after the court heard oral arguments.  The Seventh Circuit consists of Illinois, Indiana, and Wisconsin.  Same-sex marriage was already legal in Illinois before the Circuit Court's decision.  Same-sex marriages were performed in Indiana and Wisconsin after their bans were struck down by district courts and before those decisions were stayed.  Recognition of out-of-state same-sex marriage was possibly de jure legal in Indiana until Baskin v. Bogan was stayed by the Seventh Circuit.  On October 6, 2014, the Supreme Court of the United States denied cert, legalizing same-marriage in both Indiana and Wisconsin.  As a result, same-sex marriage is legal in every state within the circuit.
Title: Same-sex marriage in Ohio
Passage: Same-sex marriage in Ohio is legal under the U.S. Supreme Court ruling in "Obergefell v. Hodges", a landmark decision in which the court struck down Ohio's statutory and constitutional bans on the issuance of marriage licenses to same-sex couples on June 26, 2015.  The case was named after plaintiff Jim Obergefell, who sued the state of Ohio after officials refused to recognize his marriage on the death certificate of his husband.  Same-sex marriages were performed in Ohio beginning shortly after the Supreme Court released its ruling, as local officials implemented the order.
Title: Same-sex marriage in New Mexico
Passage: Same-sex marriage became legally recognized statewide in New Mexico through a ruling by the New Mexico Supreme Court on December 19, 2013, requiring all county clerks to issue marriage licenses to qualified couples seeking marriage regardless of gender.  Until then, same-sex couples could only obtain marriage licenses in certain counties of the state.  Eight of 33 counties, covering 58% of the state's population, had begun issuing marriage licenses to same-sex couples in August and September 2013.  New Mexico's marriage statute is not specific as to gender.  It is the only state lacking a state statute or constitutional provision explicitly addressing same-sex marriage.  Lacking a state law or judicial ruling concerning same-sex marriage prior to December 19, 2013, policy for the issuance of marriage licenses to same-sex couples was determined at the county level at the discretion of local issuing authorities.  That is, some counties recognized same-sex marriage and issued marriage licenses to same-sex couples, while others did not.  Despite the ruling by the New Mexico Supreme Court allowing same-sex marriages in the state, some of New Mexico's Native American tribes (most notably the Navajo Nation) continue to prohibit same-sex marriages within their jurisdictions and do not recognize same-sex marriages performed elsewhere.
Title: Tanco v. Haslam
Passage: Tanco v. Haslam was the lead case in the dispute of same-sex marriage in Tennessee.  A U.S. District Court granted a preliminary injunction requiring the state to recognize the marriages of the plaintiffs, three same-sex couples.  The court found the equal protection analysis used in "Bourke v. Beshear", a case dealing with a comparable Kentucky statute "especially persuasive".  On April 25, 2014, that injunction was stayed by the Sixth Circuit Court of Appeals.  "Tanco" was appealed to the Sixth Circuit, which reversed the district court and upheld Tennessee's refusal to recognize same-sex marriages from other jurisdictions on November 6.
Title: DeBoer v. Snyder
Passage: DeBoer v. Snyder is a lawsuit that was filed by April DeBoer and Jane Rowse on January 23, 2012 in federal district court, challenging Michigan's ban on adoption by same-sex couples so they can jointly adopt their children.  In August 2012, Judge Bernard A. Friedman invited the couple to amend their suit to challenge the state's ban on same-sex marriage, "the underlying issue".  Following a hearing on October 16, 2013, Friedman scheduled a trial that ran from February 25 to March 7, 2014.  On March 21, Judge Friedman issued his ruling overturning the ban.  On March 22, the United States Court of Appeals for the Sixth Circuit placed a temporary hold on Judge Friedman's ruling.  The appeal was argued on August 6.  On November 6, the Sixth Circuit reversed Judge Friedman and upheld Michigan's ban on same-sex marriage.
Title: Bourke v. Beshear
Passage: The lead cases on same-sex marriage in Kentucky are Bourke v. Beshear, and its companion case Love v. Beshear.  In "Bourke", a U.S. district court found that the Equal Protection Clause requires Kentucky to recognize valid same-sex marriages from other jurisdictions.  In "Love", the same court found that this same clause renders Kentucky's ban on same-sex marriage unconstitutional.  Both decisions were stayed and consolidated upon appeal to the Sixth Circuit Court of Appeals, which heard oral arguments in both cases on August 6, 2014.  On November 6, the Sixth Circuit upheld Kentucky's ban on same-sex marriage.
Title: Same-sex marriage in the Sixth Circuit
Passage: On April 28, 2015, the Supreme Court of the United States heard oral arguments for "Obergefell v. Hodges" (Ohio), which was consolidated with three other same-sex marriage cases from the other states in the Sixth Circuit: "Tanco v. Haslam" (Tennessee), "DeBoer v. Snyder" (Michigan), "Bourke v. Beshear" (Kentucky).  On June 26, 2015 the Supreme Court reversed the Sixth Circuit's decision, paving the way for same-sex marriage to become legal in those states, and setting a precedent for the entire nation.  All four states complied with the ruling the same day it was issued before the mandate was actually issued.  Every state in the circuit had a district court ruling against their states' ban, but they were eventually stayed pending appeal.  The Sixth Circuit consists of Kentucky, Michigan, Ohio, and Tennessee.  On August 6, 2014, the Sixth Circuit heard oral arguments for same-sex marriage cases from each state within the circuit.  On November 6, 2014, the Sixth Circuit in a split 2-1 decision, upheld the states' same-sex marriage bans, reversing the district courts' rulings that struck them down.  The Sixth Circuit was the first and only circuit court since the landmark ruling "United States v. Windsor" to uphold the constitutionality of states' same-sex marriage bans which caused a circuit split.
Title: Same-sex marriage in Arkansas
Passage: Same-sex marriage in Arkansas is legal under the U.S. Supreme Court decision in "Obergefell v. Hodges", a landmark case in which same-sex marriage bans were struck down on June 26, 2015.  Prior to that, same-sex marriage in Arkansas was briefly legal for a period beginning on May 9, 2014, as the result of a ruling by Sixth Judicial Circuit Judge Chris Piazza, striking down the state's constitutional and legislative ban on same-sex marriage as violating the Constitution of the United States.  Approximately 541 same-sex couples received marriage licenses in several Arkansas counties before the Arkansas Supreme Court stayed his ruling pending appeal on May 16, 2014.
Title: Same-sex marriage in Canada
Passage: Same-sex marriage in Canada was progressively introduced in several provinces by court decisions beginning in 2003 before being legally recognized nationwide with the enactment of the "Civil Marriage Act" on July 20, 2005.  On June 10, 2003, the Court of Appeal for Ontario issued a decision immediately legalizing same-sex marriage in Ontario, thereby becoming the first province it was legal.  The introduction of a federal gender-neutral marriage definition made Canada the fourth country in the world, and the first country outside Europe, to legally recognize same-sex marriage throughout its borders.  Before the federal recognition of same-sex marriage, court decisions had already introduced it in eight out of ten provinces and one of three territories, whose residents collectively made up about 90% of Canada's population.  More than 3,000 same-sex couples had already married in those areas before the "Civil Marriage Act" was introduced.  Most legal benefits commonly associated with marriage had been extended to cohabiting same-sex couples since 1999.
Title: Same-sex marriage by Circuit Court
Passage: Prior to the landmark ruling "United States v. Windsor", the constitutionality of banning same-sex marriage was upheld by the Eighth Circuit in "Citizens for Equal Protection v. Bruning".  After the "Windsor" ruling, many same-sex marriage bans were struck down by lower courts.  The Tenth, Fourth, Seventh, and Ninth circuits all ruled that same-sex marriage bans were unconstitutional.  The cases that made it to these circuit courts originated in district courts which for the most part also struck down same-sex marriage bans.  When a circuit court struck down a state's same-sex marriage ban, it did not directly strike down same-sex marriage bans in other states within the circuit.  However, it paved the way for same-sex marriage bans to be struck down in the entire circuit due to the precedent it set for district courts within the circuit to follow.  In some states, same-sex marriage was already legal before a federal circuit court ruled on the matter.  The Sixth Circuit ruled that same-sex marriage bans were not unconstitutional and reversed the district court rulings that struck down same-sex marriage bans.  Since this was the only circuit court to rule this way post-"Windsor", this created a circuit split which ultimately led to the Supreme Court of the United States deciding to resolve the issue once and for all.  They ruled that same-sex marriage bans violate the constitution in the landmark ruling "Obergefell v. Hodges" which was the consolidated case that covered each state in the Sixth Circuit.  Some circuit courts have not ruled on the constitutionality of same-sex marriage bans at all.  Many circuit courts had pending same-sex marriage cases, but decided to hold off on litigation until the Supreme Court ruled on the matter.
Same-sex marriage in the Sixth Circuit Same-sex marriage in Ohio