WASHINGTON — When a federal court ruled on Louisiana's ban on same-sex couples' marriages earlier this month, something shocking happened: The judge upheld the ban.

U.S. District Court Judge Martin Feldman ruled the state's marriage ban was constitutional — issuing the first federal court decision examining the question and finding such a ban to be constitutionally permissible in more than a year.

Even he realized this was an unusual decision. "It would no doubt be celebrated to be in the company of the near-unanimity of the many other federal courts that have spoken to this pressing issue," Feldman wrote in his opinion.

Since the U.S. Supreme Court struck down part of the Defense of Marriage Act and dismissed the California Proposition 8 case on a technicality in June 2013, federal judges all across the country have thrown out bans on marriage for same-sex couples and bans on the recognition of marriages performed out of state, creating an avalanche of decisions rolling toward the Supreme Court. Judges from Texas to Michigan and from Oregon to Florida have ruled marriage bans unconstitutional. The nation's top lawyers are jockeying for their cases to become The Case.

The direction and pace of the marriage decisions — their sheer velocity — is unlike any other debate in modern politics or law. In the space of a little more than a year, the timeline for any sort of legal resolution of the issue has completely shifted.

And now, on Sept. 29, the Supreme Court justices are due to consider whether to hear one or more of a handful of marriage cases that could produce the final blow. The marriage equality movement — work that began decades earlier and was full of setbacks, including DOMA itself, along the way — is on the precipice of becoming a reality.

Fifteen months ago, very few imagined this rapid a timeline. But the decisions that day, specifically what Justices Anthony Kennedy and Antonin Scalia wrote, ultimately opened the floodgates for what followed. Of DOMA, Kennedy declared the law unconstitutional because it "instructs all federal officials, and indeed all persons with whom same-sex couples interact, including their own children, that their marriage is less worthy than the marriages of others." And in his dissent to that opinion, Scalia noted "how easy it is, indeed how inevitable, to reach the same conclusion with regard to state laws denying same-sex couples marital status."

That's exactly what's happened.

Since then, three federal appeals courts and nearly every federal trial judge to consider whether state bans on same-sex couples' marriages are permitted has declared them to be unconstitutional.

It didn't necessarily follow from the DOMA decision in United States v. Windsor that this state of things was inevitable. Defenders of state bans — particularly in the immediate aftermath of the Windsor ruling — argued that Kennedy's opinion was as much about federalism, about leaving marriage decisions to the states, as it was about equal protection of the laws.

But it didn't even take an entire month for the first decision to come down.

Only weeks after Windsor, U.S. District Court Judge Timothy Black ruled on the case of an Ohio couple, who legally married in Maryland. One of the men, John Arthur, was in hospice care, "certain to die soon" from ALS. The couple sued Ohio to recognize their marriage on Arthur's inevitable death certificate.

Writing that it was "not a complicated case," Judge Black concluded that the purpose of Ohio's 2004 amendment banning same-sex couples from marrying is "'to impose inequality' and to make gay citizens unequal under the law." In his decision, Black even cited Scalia's words, noting, "[J]ust as Justice Scalia predicted in his animated dissent, by virtue of the present lawsuit, 'the state-law shoe' has now dropped in Ohio." Their case — the matter of one death certificate — was one of a handful of moments that brought the movement from the DOMA decision day to today's near-unanimity.

Black's decision ordered recognition of their marriage under a temporary restraining order, a court action that cannot generally be appealed. But even after Arthur's death in October 2013, Ohio officials continued fighting the case. Black issued a permanent injunction — a decision that could be and has been appealed to a higher court.

Days earlier, however, a federal judge handed down the ruling that — in retrospect — dramatically altered the national landscape for marriage, providing a cataclysmic force for federal judges in the United States.

On Dec. 20, 2013, a Friday afternoon, U.S. District Court Judge Robert J. Shelby ruled that Utah's ban on same-sex couples' marriages, passed by voters in 2004, is unconstitutional.

"[A]ny regulation adopted by a state," Shelby wrote, "whether related to marriage or any other interest, must comply with the Constitution of the United States." Taking on the federalism argument, he wrote that the rights of the individual must take precedent over states' rights when they're in conflict.

In deciding the ultimate question, Shelby went even further, concluding that Utah "provided no evidence that opposite-sex marriage will be affected in any way by same-sex marriage. In the absence of such evidence, the State's unsupported fears and speculations are insufficient to justify the State's refusal to dignify the family relationships of its gay and lesbian citizens."

Then, Shelby did something that changed the path forward for marriage equality and may have — intentionally or inadvertently — sped up the course of equality more than almost any other single step since the Windsor decision: Shelby refused to put the ruling on hold while the state appealed his decision. If the decision in the constitutional question set the case on its course, the secondary decision not to issue a stay of the ruling set the pace.

Couples rushed to the Salt Lake County Clerk's Office that Friday seeking out marriage licenses, including J. Seth and Michael Adam Ferguson — who became the first same-sex couple to marry in Utah. They live-tweeted the experience — which included officials at first uncertain about their authority to issue a license.

Judge Shelby formally denied the state's request to stop the ruling from going into effect while the state appealed on Dec. 23. The 10th Circuit Court of Appeals did the same, denying the request on Christmas Eve. The Supreme Court eventually granted the request on Jan. 6, but even the justices took their time in doing so, leading to what Derek Kitchen — a plaintiff in the Utah marriage case who is seeking to marry his partner, Moudi Sbeity — called "17 days of euphoria." In all, more than 1,300 same-sex couples in Utah received marriage certificates before the stay was issued.

Shelby's decision not to issue a stay, reinforced by the 10th Circuit, has empowered federal judges in other states — including Indiana, Michigan, Oregon, Pennsylvania, and Wisconsin — to do the same, as have state judges in Arkansas and Colorado. From Ann Arbor, Michigan, to Carroll County, Arkansas, same-sex couples got marriage licenses that many had never expected to see in their lifetimes.

Eventually, in all those states but Oregon and Pennsylvania (where state officials have made no appeals), appellate judges halted marriages in the states for the time being. But judges have asserted that holding off on implementing overturned bans was not justified; same-sex couples have been married in 25 states and the District of Columbia; and the Department of Justice elected to recognize the marriages of couples in Utah and in some of the other states. Coming from many angles, in many states, all over the country, the idea of marriage equality has become inevitable, a reality on the ground even before the legal issue is formally settled.

By time the federal appeals courts began hearing marriage arguments in April of this year, the national conversation appeared to be focused on "how" the question will be resolved legally, not "if."

The 10th Circuit, followed by the 4th Circuit and, most recently, the 7th Circuit all have ruled marriage bans unconstitutional in the past three months. The 9th Circuit is expected to strike down Idaho and Nevada's bans. Only the 6th Circuit — where the court's key judge appeared conflicted at oral arguments over the Kentucky, Michigan, Ohio, and Tennessee bans — potentially stands apart.

The speed with which all of these cases have moved forward — the 7th Circuit decision came down just nine days after the arguments in the case — has meant that the issue already is back at the Supreme Court. State or local officials in Indiana, Oklahoma, Utah, Virginia, and Wisconsin have asked the Supreme Court to hear their respective appeal of the marriage case in their state. The same-sex couples, moreover, agree: All of the plaintiffs challenging the bans have asked the justices to resolve the issue.

And so this unstoppable force of marriage equality will be meeting what could be an immovable object — the Supreme Court — on Sept. 29, when the justices consider whether to take any of the cases before the court.

On Tuesday in Minnesota, Justice Ruth Bader Ginsburg, who joined Kennedy's opinion striking down DOMA in 2013, marveled at the "remarkable" shift in public opinion on marriage. But she noted that, if all appeals courts continued to be in agreement on the issue, there would be "no need for [the justices] to rush" on the issue. If the 6th Circuit upheld marriage bans, however, she said, the decision actually could have the result of adding "some urgency" to the issue for the justices.

The justices could decide to take a case on Sept. 29; they could deny the requests to take all of the appeals, which would lead to same-sex couples being able to marry in those states; or they could hold the cases for the future — awaiting a decision from the 6th Circuit, perhaps.

But the "remarkable" shift that Ginsburg described is one that exists across the nation, from the public to the lower courts. And though Ginsburg — in a technical, legal sense — might not see "urgency" to take a case immediately, the filings by the state officials and plaintiffs in the cases show that they have a sense of urgency and are looking for resolution.

Timothy Bostic, who is challenging Virginia's marriage ban with his partner Tony London, spoke at a news conference a year ago regarding their challenge. Summing up the issue with a simplicity that echoes across the lawsuits and plaintiffs seeking marriage equality across the county, Bostic told the reporters assembled, "We filed this lawsuit because, although we've been together for more than two decades, we want our relationship to be recognized, just like everyone else's. We want to be married."