Update (June 26): The Supreme Court ruled today that the Massachusetts "buffer law" is unconstitutional, arguing that sidewalks and public streets present public forums and that, in regulating their use broadly, the state's law violates the First Amendment.
"A painted line on the sidewalk is easy to enforce, but the prime objective of the First Amendment is not efficiency," Chief Justice John Roberts argued in a court document. "Given the vital First Amendment interests at stake, it is not enough for Massachusetts simply to say that other approaches have not worked."
According to Roberts:
It is no accident that public streets and sidewalks have developed as venues for the exchange of ideas. Even today, they remain one of the few places where a speaker can be confident that he is not simply preaching to the choir. With respect to other means of communication, an individual confronted with an uncomfortable message can always turn the page, change the channel, or leave the Web site. Not so on public streets and sidewalks. …
Petitioners wish to converse with their fellow citizens about an important subject on the public streets and sidewalks—sites that have hosted discussions about the issues of the day throughout history. Respondents assert undeniably significant interests in maintaining public safety on those same streets and sidewalks, as well as in preserving access to adjacent healthcare facilities. But here the Commonwealth has pursued those interests by the extreme step of closing a substantial portion of a traditional public forum to all speakers. It has done so without seriously addressing the problem through alternatives that leave the forum open for its time-honored ...1