The Supreme Court unanimously ruled against Massachusetts's abortion clinic "buffer zone" law on Thursday, determining that the law as written violates the First Amendment of the Constitution. The 2007 state law places a 35-foot protester-free zone around abortion-providing women's clinics. Although the law itself was a response to aggressive harassment of clinic patients and employees from anti-abortion protesters in the state, it was challenged in court by a "grandmotherly" 77-year-old activist named Eleanor McCullen who uses a quieter method to confront patients. 

The ruling itself is relatively narrow, according to SCOTUSblog.  Essentially, states may pass laws that protect access to clinics, but not laws that prohibit speech on public sidewalks as the law in question does. "The buffer zones burden substantially more speech than necessary to achieve the Commonwealth’s asserted interests," Chief Justice Roberts's opinion reads.

To separate out the issues of safety and speech, the court made a distinction between "protesters" and "petitioners" in its decision. "Petitioners," like McCullen, are described by Chief Justice Roberts's decision as gentler. On a quick look of the decision, it seems like their speech is primarily the one in question for Roberts when considering the law's First Amendment violation: 

Some of the individuals who stand outside Massachu­setts abortion clinics are fairly described as protestors, who express their moral or religious opposition to abortion through signs and chants or, in some cases, more aggres­sive methods such as face-to-face confrontation. Petition­ers take a different tack. They attempt to engage women approaching the clinics in what they call “sidewalk coun­seling,” which involves offering information about alterna­tives to abortion and help pursuing those options. Petitioner Eleanor McCullen, for instance, will typically initiate a conversation this way: “Good morning, may I give you my literature? Is there anything I can do for you?"

While Roberts and the Court acknowledge that Massachusetts has a legitimate interest in maintaining public safety in this case, they conclude that the state could use less "extreme" methods to protect women accessing abortion clinics, ones that would still allow McCullen to follow patients to the door as they seek care. Roberts rejected the state's argument that those other methods have not worked in their state, writing that "the Commonwealth has pursued those interests by 
the extreme step of closing a substantial portion of a tradi­tional public forum to all speakers...without seriously addressing the problem through alternatives that leave the forum open for its time-honored purposes."

The anti-abortion activists challenging the law had also asked the Supreme Court to strike down its earlier ruling upholding the constitutionality of some state buffer zone laws, and to declare all such zones unconstitutional. Today's ruling does not take that broader step. 

Here's our background on the challenge. And here is the full opinion