The U.S. Supreme Court unanimously struck down a Massachusetts state law that imposed a 35-foot buffer zone around abortion clinics, in which protestors and pro-life counselors could not enter to speak with patients.

The law violates First Amendment free speech protections, the court said in its McCullen vs. Coakley opinion, delivered June 26 by Chief Justice John Roberts, Jr.

Although it did not strike down all buffer laws, the court said that the Massachusetts regulation is unconstitutional, stressing that sidewalks and public ways are key forums for free speech.

In 2007, Massachusetts amended existing law and made it a crime to "knowingly stand on a 'public way or sidewalk' within 35 feet of an entrance or driveway to any 'reproductive health care facility.'" This barred pro-life sidewalk counselors from distributing literature and having personal conversations with women entering the building anywhere within this distance of the clinic.

The state's brief on the case argued that the law was "justified solely by legitimate government interests in public safety and health care access."

However, pro-life challengers to the law said that it infringed upon their constitutionally-protected First Amendment right to the freedom of speech. They argued in a legal brief that the law "indiscriminately criminalizes even peaceful, consensual, non-obstructive conversation and leafleting" and that it unfairly targeted certain kinds of speech, namely, pro-life counseling and views.

The U.S. Court of Appeals for the First Circuit upheld the buffer law in January 2013, ruling that the First Amendment does not guarantee an audience "available at close range," and arguing that pro-life counselors still have access to women seeking abortions, even with the 35-foot buffer zone in place.

However, the Supreme Court overturned the appellate court's ruling in a rare unanimous vote, saying that the law restricted speech on public streets and sidewalks.

"It is no accident that public streets and sidewalks have developed as venues for the exchange of ideas," the court opinion stated. "Even today, they remain one of the few places where a speaker can be confident that he is not simply preaching to the choir."

The buffer zone law imposed "serious burdens" on the free speech of pro-life sidewalk counselors, inhibiting their ability to conduct "close, personal conversations that they view as essential to 'sidewalk counseling,'" as well as their ability to distribute literature, the court said.

Calling the law "extreme," the ruling said that the legislation shut off "a substantial portion of a traditional public forum to all speakers" and failed to find an alternative that would "leave the forum open for its time-honored purposes."

"Petitioners are not protestors," the court opinion said. "They seek not merely to express their opposition to abortion, but to inform women of various alternatives and to provide help in pursuing them."

"Petitioners believe that they can accomplish this objective only through personal, caring, consensual conversations. And for good reason: It is easier to ignore a strained voice or a waving hand than a direct greeting or an outstretched arm. If all that the women can see and hear are vociferous opponents of abortion, then the buffer zones have effectively stifled petitioners' message."