(CNN) -- The Supreme Court on narrow grounds struck down a Massachusetts law Thursday creating
no-protest "buffer zones" on public property surrounding health clinics that perform abortions.
In what is a free speech dispute that touched on the larger political and social controversy over abortion, the court ruled unanimously.
It did not strike down all such laws, but the ruling gives room for the state to go back and craft new, less restrictive protest zones.
"Here the commonwealth has pursued those interests by the extreme step of closing a substantial portion of a traditional public forum to all speakers," said Chief Justice John Roberts. "It has done so without seriously addressing the problem through alternatives that leave the forum open for its time-honored purposes."
Massachusetts officials said the issue was more about public safety and pedestrian access on local sidewalks. Anti-abortion supporters countered that their First Amendment rights were violated.
The decision could affect a broader range of free speech areas -- over issues such as war, taxes, corporate bailouts and elections -- where the location of the message is often key to its effectiveness.
Eleven women's health clinics across Massachusetts are covered by the fixed buffer zones.
The current state law strengthened earlier restrictions that had created a floating 6-foot protective bubble around clinic patrons approaching the facility.
Abortion rights supporters said it was ineffective, since they claimed it led to blocked entrances and a gauntlet of protesters surrounding patients and staff.
Some past anti-abortion protests have turned violent in the United States.
The state's 2007 revised "selective exclusion law" makes it a crime for speakers other than clinic "employees or agents ... acting within the scope of their employment" to "enter or remain on a public way or sidewalk" within 35 feet of "a reproductive health care facility."