Pro Life supporters rally at a Planned Parenthood facility, Downtown, in February.

A federal judge has upheld a Pittsburgh ordinance establishing a 15-foot “buffer zone” designed to keep abortion protesters away from clinic entrances  — the latest round in a three-year legal fight.

In a 26-page opinion Thursday, U.S. District Judge Cathy Bissoon wrote that the city’s 2005 ordinance “imposes only a minimal burden” on protesters trying to persuade women not to have abortions.

While the ordinance bars protesters from following women across a brightly painted 15-foot boundary, she said, clinic protesters’ “own records reflect not only that they are able to communicate with patients, but, in some instances, have persuad[ed] women not to have abortions.”

The protesters argued that they could persuade more women not to abort “if they could walk alongside patients all the way to and from the entrance of the clinic,” Judge Bissoon added. But they “offer no concrete evidence to support this claim.”

Abortion-rights supporters and city officials hailed the decision.

“We thank the court for this decision, which retains a great benefit for women and health care access in Pittsburgh,” said Timothy McNulty, spokesman for Mayor Bill Peduto.

“No women should have to endure threats, confrontation or even violence when they seek basic reproductive health-care services,” said Kimberlee Evert, president and CEO of Planned Parenthood of Western Pennsylvania. “This court decision ensures those who need medical counseling or treatment will have safe, unfettered access to our clinics.”

The Alliance Defending Freedom, which represented clinic protesters, remained defiant. “The government can’t stifle free speech simply because some pro-abortion politicians or activists demand it,” it said in a statement. “We are consulting with our clients regarding the possibility of appeal.”

The fight over the buffer zone began in 2014. That June, the U.S. Supreme Court overturned an expansive statewide buffer zone law in Massachusetts. That opened the door to renewed scrutiny of similar buffers elsewhere. Pittsburgh’s buffer was challenged in that September, when Nikki Bruni and other self-described “sidewalk counselors” said it violated their First Amendment rights.

Judge Bissoon initially dismissed the case, but in June 2016, the 3rd U.S. Circuit Court of Appeals reinstated it. The appellate judges ruled that before the case could be decided, the city had to justify its buffer zones by showing they served a legitimate public interest and that it had reasons for not using other approaches that might be less restrictive.

Judge Bissoon’s decision Thursday laid out that groundwork, citing 2005 City Council testimony that, in the nine months leading up to the 2005 ordinance’s passage, there had been “13 cases of aggressive pushing, shoving and hitting, and 30 complaints of harassing behavior” outside clinics. The city, she wrote, had tried other approaches — such as stationing police at clinics — that had proved to be impractical. And the city’s buffer zones, she said, were smaller than those overturned in Massachusetts.

Since “the current law burdens very little speech to begin with,” she concluded, “there is no reason to believe that [other] measures would burden substantially less speech.”