DETROIT, MI -- The state must fully recognize the marriages of couples who wed on the one day it was legal in Michigan last year, U.S. District Judge Mark A. Goldsmith ordered in a preliminary injunction issued Thursday.

The injunction won't take effect for 21 days, but unless an appeals court further stays the decision, it means the state will have to provide spousal benefits to same-sex couples who got married on March 22, 2014.

Some 300 couples received marriage licenses that day, after a federal judge struck down the state's same-sex marriage ban, and before an appeals court put that ruling on hold in a case that's currently in the hands of the U.S. Supreme Court.

Clerks in Oakland, Muskegon, Washtenaw and Ingham counties opened their doors that Saturday to issue the licenses.

Michigan Attorney General Bill Schuette sought to void those marriages in November, after the U.S. 6th Circuit Court of Appeals upheld the gay marriage ban.

But Goldsmith ruled that "what the state has joined together, it may not put asunder."

"This Court concludes that the continued legal validity of an individual's marital status in such circumstances is a fundamental right comprehended within the liberty protected under the Due Process Clause of the Fourteenth Amendment," Goldsmith ruled.

"Even though the court decision that required Michigan to allow same-sex couples to marry has now been reversed on appeal, the same-sex couples who married in Michigan during the brief period when such marriages were authorized acquired a status that state officials may not ignore absent some compelling interest -- a constitutional hurdle that the defense does not even attempt to surmount. In these circumstances, what the state has joined together, it may not put asunder."

(Full ruling marriage recognition ruling.pdf .)

The state could appeal the decision.

"We are reviewing Judge Goldsmith's decision but as I have said repeatedly, the sooner the United States Supreme Court makes a decision on this issue the better it will be for Michigan and America," Schuette said in a statement.

The U.S. Supreme Court is expected to hold a conference Friday and decide whether it will review the case that challenged the constitutionality of Michigan's voter-approved gay marriage ban.

That case was filed by Hazel Park couple April DeBoer and Jayne Rowse, who sued the state because they can't jointly adopt their three children without a legal marriage in Michigan.

It led to the one spring day when same-sex marriage was legal in Michigan.

Then in April, eight newly married couples sued the state in April for denying them spousal benefits, primarily insurance benefits, despite acknowledging that the marriages were performed legally.

Their case, the couple's ACLU lawyers argued, was not about a right to get married, but a right to stay married.

That led to Goldsmith's Thursday's decision.

"These marriages are cherished and valid--same as any other--and it's only right that the courts and our country recognize as much," said ACLU lawyer Jay Kaplan after the ruling. "All these couples have ever asked is that they be able to love and protect their families without being discriminated against. With this decision, they can finally begin to move away from uncertainty and unfairness and toward the fulfillment of their shared dreams."