LGBT legal activists were surprised and disappointed last week when two of the U.S. Supreme Court’s most reliably pro-LGBT justices joined with conservatives on the bench to stay on a significant lower court decision that said federal law prohibits discrimination based on gender identity.

The case involves a Virginia student, Gavin Grimm, who seeks the right to use restrooms at his public high school that correspond to his gender identity. The Fourth Circuit U.S. Court of Appeals said the Title IX prohibition of discrimination “on the basis of sex” in schools includes discrimination based on the gender with which a student identifies.

On August 3, in a 5 to 3 vote, the Supreme Court granted a preliminary injunction that blocks the Fourth Circuit decision from taking effect until the court decides either to review the decision itself or votes to leave the decision in place.

Agreeing to the stay were Justice Anthony Kennedy, who has authored several landmark decisions that have secured important rights for LGBT people, and Justice Stephen Breyer, who has voted with Kennedy on those decisions and others that have benefited LGBT people. The three conservatives voting for the stay were Chief Justice John Roberts and Justices Clarence Thomas and Sam Alito.

Next the court must decide whether to review the Fourth Circuit decision on its merits. That vote (called granting a petition of cert) could happen this fall and requires only four justices to agree.

While five justices agreed to the stay, that does not guarantee the same five justices will vote to review the case. Kennedy made no comment concerning his vote, but Breyer attached a statement to the August 3 order, saying his vote was a “courtesy” that would simply “preserve the status quo.”

The statement implied the court being in recess prompted his courtesy, but he also indicated that he knew four justices had already voted to grant the stay so he knew his vote was the necessary fifth vote to grant the stay.

But a number of court observers, including Jon Davidson of Lambda Legal, point out that Breyer’s brief statement made reference to his dissent in a death penalty case.

“Such ‘courtesy’ votes are fairly common in death penalty cases,” noted Center for American Progress fellow Ian Millhiser in a ThinkProgress.com essay. They “prevent a situation where the Court announces that it will hear a capital case, only to have that case become moot after the inmate at issue in that case is executed….”

However, Gavin Grimm starts his senior year of high school August 31. The school district does not have to file its petition to the Supreme Court, for review of the Fourth Circuit decision, until August 29. During the several months it takes for other briefs to be filed and the justices to discuss whether to take the case, Grimm will be barred from using the boys’ restroom. (The school district has designated three “unisex” restrooms for use by Grimm and any other student. Grimm says this stigmatizes him and undermines his effort to transition to and be accepted as male.)

If the justices refuse the school district’s petition for review, the Fourth Circuit decision will go into effect and Grimm will be free to use the boys’ restroom. If the Supreme Court decides to review the Fourth Circuit decision, it will not likely be able to rule on the case until the end of Grimm’s senior year.

Grimm is a senior this fall at Gloucester High School in the rural Virginia county of Gloucester. He’s 17 years old and, though physically female since birth, he has, since age 6, felt that he’s a male.

A psychologist diagnosed Grimm with gender dysphoria, a condition in which a person strongly identifies as a gender different from his or her physical gender attributes. His parents helped him change his name, secure treatment to enable him to transition to a male identity, and sought help from school officials. School officials were helpful until parents of some other students began to complain about Grimm’s being allowed to use the boys’ restrooms. Then, the school board adopted a policy requiring that transgender students use “an alternative appropriate private facility.”

With the help of the ACLU, Lambda Legal, the National Center for Lesbian Rights, and others, Grimm filed suit. A federal district court dismissed his case, but the Fourth Circuit reversed that dismissal and sent the case back to district court, urging it to issue a decision on the merits of Grimm’s Title IX argument as quickly as possible.

Now, Gloucester has won a stay of that directive and has until August 29 to ask for Supreme Court review of the lower court decisions.

Add to this one other twist: There’s a possibility that, if the court agrees to hear the case, a court vacancy left by the death of Justice Antonin Scalia, will be filled in time to hear argument in the case. That likelihood is deeply complicated by the current Republican Senate blockade against all Obama judicial nominees and the status of a very volatile presidential campaign that won’t be resolved until November 8.

The possibility of the Senate confirming Obama’s named nominee (Merrick Garland) is not likely until after November 8. And though there is little chance that a decision could be rendered before the end of Grimm’s senior year, the issue is still critical for many transgender students now and into the future.

Why? Because the Fourth Circuit said that Title IX of the Education Amendments Act of 1972 –which prohibits discrimination based on sex by federally funded educational institutions— also prohibits discrimination based on gender identity was a big victory for LGBT people. It was the first time a federal appeals court anywhere in the nation had ruled that an already existing federal law prohibiting discrimination based on “sex” included discrimination based on “gender identity.”

When that Fourth Circuit decision was released in April, LGBT legal advocates thought there was little chance the Supreme Court would accept an appeal of it. The case was (and is still) in a preliminary stage and, at that time, the Fourth Circuit decision did not conflict with an opinion of any other circuit in the nation. And, with the Supreme Court having only eight members, a tie vote would uphold the Fourth Circuit decision.

There’s still no conflict among the circuits and that, said NCLR Legal Director Shannon Minter, makes the possibility that the Supreme Court will review the case “less likely” still.

But Minter and Lambda’s Davidson acknowledge some disappointment over the grant.

“The vote is certainly sobering,” said Minter.  “That said, I am cautiously optimistic the court will not take review and ultimately quite optimistic the court will affirm that that Title IX protects transgender students when they do take up a case.”

Davidson said he is “very disappointed” in the stay but said the fact that only eight justices are on the court makes a 4 to 4 vote on the merits of the case a real possibility. And a tie vote leaves the lower court decision intact.

“This makes it less likely that review will be granted in close cases, something Supreme Court scholars have noted has been happening since Justice Scalia’s death,” said Davidson. “So, at the moment, it’s very hard to tell whether the Supreme Court will actually decide to hear a challenge to the correctness of the Fourth Circuit’s decision.”