The Supreme Court’s surprising move to pass on deciding whether state prohibitions on same-sex marriage violate the U.S. Constitution may reflect two things about the justices: a natural inclination for incremental steps and a worry on the part of conservatives that the battle — for now — appears lost.

Many observers of the court were stunned that the justices passed up reviewing lower-court decisions that overturned prohibitions on same-sex marriage in five states, delaying a decision that would answer the question for the nation.

Gay rights proponents took it as a sign that the court likes to move slowly when endorsing momentous societal change, that it feels no need to decide an issue before it must — and that the court’s move provides a clear signal for future challenges of voter-approved prohibitions on same-sex marriage.

“An action like this is profound,” said Mary Bonauto, a lawyer with Gay & Lesbian Advocates & Defenders (GLAD). “I expect that lower courts will get the message.”

Marriages could soon be available in six more states, for a total of 30. The Williams Institute at the University of California at Los Angeles estimates that when the rollout is complete, 65 percent of gay couples and a majority of all Americans will live in a place where same-sex unions are legal.

Same-sex marriage status in the U.S., state-by-state

To some, it seems impossible that that fact would have escaped the attention of the justices.

“There is something called the ‘normative power of the actual,’” said Walter Dellinger, a solicitor general in the Clinton White House. “People get used to an idea over time, and they come to think it’s right.” That is what will happen as more Americans see same-sex marriage as positive or, perhaps, simply inconsequential, Dellinger said.

“And when the time comes, the Supreme Court will declare a right to same-sex marriage,” he said.

The news that the Supreme Court would not review constitutional decisions from federal appeals courts in Denver, Richmond and Chicago came in a most inauspicious way. It was buried in an 81-page list of cases the justices had rejected, with no explanation or recorded dissent.

“There is no way to know why the court did what it did,” said Jim Campbell, a senior attorney for the Alliance Defending Freedom, a conservative legal organization defending the state bans. “The issue is still whether people in America can continue to define marriage as between a man and a woman.”

Suzanna Sherry, a constitutional law expert at Vanderbilt University, warned against interpreting something that is not there. The idea that the court had to accept the cases at this time “represents a mistaken view of the Supreme Court and its interpretation of its role.”

She said, “It is not for them to reach out to decide cases when lower courts have been unanimous so far.”

Yolanda Pascua, left, and Laekin Rogers get married at the Salt Lake County clerk's office in Salt Lake City on Oct. 6. Same-sex couples in Utah are celebrating after the U.S. Supreme Court cleared the way for gay marriages to begin in this state. (Rick Bowmer/AP)

But in practice, the court has taken cases before without a split in the appeals courts, on issues far less important than the fundamental right to marry.

And it is hard to think that the action carried no strategic importance. By putting holds on marriages in Virginia and Utah — lower courts had stayed the action in other states — the court had hinted that it did not want more same-sex unions to occur until it had a chance to weigh in.

There was enormous pressure on the court to take the case. The winners and losers in all five states had urged the court to get involved — a flock of high-profile lawyers had written the briefs asking for review. More than 30 states and a like number of the country’s biggest companies had asked the court to settle the issue for the nation.

“I’m astonished,” said Richard Fallon, a Harvard law professor who is a student of the court. Neither side of the court’s ideological split has enough motive to insist that the issue be taken up now, he believes.

“There are some justices who aren’t in any hurry to take this, and four who are worried they are going to lose,” Fallon said.

The four are the court’s consistent conservatives, who were in the minority in June 2013 when the justices struck down part of the Defense of Marriage Act, which withheld federal recognition of same-sex marriages performed in states where it was legal.

Justice Anthony M. Kennedy wrote the opinion in U.S. v. Windsor for the court’s liberals, and an angry dissent from Justice Antonin Scalia warned that Kennedy was arming challengers of state prohibitions.

His prediction proved right, as a string of decisions in federal courts disallowed same-sex marriage bans.

Those four votes would have been enough to take any of the cases rejected Monday. But it takes five votes to win.

It is hard not to think about Monday’s action without remembering two others among the court’s most controversial decisions.

One was the court’s decision in Loving v. Virginia, in which it struck down state bans on interracial marriage in 1967. Demonstrating the same preference for incremental change it is showing in the same-sex marriage debate, the justices waited until such bans were pretty much a relic, confined to 16 states mostly in one region of the country. The court passed up several opportunities to step in.

With same-sex marriage, a similar situation may soon exist, with one important caveat: While public polls at the time of Loving showed that the public was still opposed to interracial marriage, public support for same-sex marriage has dramatically increased, especially among the young.

The other decision is Roe v. Wade. Justice Ruth Bader Ginsburg for years has said that the sweeping decision in the case hardened opposition to abortion by making it a national issue. She acknowledges that several studies have seriously questioned her premise, but she continues to hold that it was “too far, too fast.”

Last month, Ginsburg surprised an audience by saying there was “no urgency” in addressing the marriage petitions at the court. The justices could confront the question if an appeals court upheld one of the bans and set up an obvious split.

Some wondered whether Ginsburg had misspoken. It turns out she was serious.