Several Supreme Court justices appeared skeptical Wednesday about the constitutionality of Massachusetts' 35-foot buffer zone around abortion clinics in a case that has broad First Amendment ramifications.

Massachusetts instituted its 2007 buffer zone law after several abortion clinics in the state complained that protesters, activists and others repeatedly were blocking — and sometimes harassing — patients as they entered their facilities.

The state said in some instances before the law was enacted, protesters had thrown anti-abortion leaflets into car windows and sometimes poked their heads or hands inside the vehicles.

Eleanor McCullen, a 77-year-old anti-abortion activist, challenged the Massachusetts' law on the grounds it violated her free speech rights.

During oral arguments for her case, liberal and conservative-leaning jurists questioned whether the state could find less restrictive ways to ensure patients have safe access to the clinics while protecting free-speech rights of peaceful anti-abortion protestors and others gathered outside.

"Surely you could have a law against screaming and shouting within 35 feet or protesting within 35 feet" that also would permit nonviolent demonstrations, Justice Antonin Scalia said. "What this case involves, what these [anti-abortion activists] want to do, is to speak quietly and in a friendly manner, not in a hostile manner."

Massachusetts Assistant Attorney General Jennifer Miller argued it would be "very difficult" to write a statue that would prohibit some types of speech, such has yelling, while allowing others, such as quiet, peaceful dialogue.

"At some point or another, the [state] legislature was aware that some amount of space needed to be created, and it chose 35 feet as a reasonable response, a reasonable amount of space around the facility," she said.

Miller added the law doesn't ban free speech but "moved [conversations] back a few feet."

Justice Elena Kagan responded that the buffer's size was "more than a few feet."

"You know, 35 feet is a ways," she said. "That's a lot of space."

Critics of the law say that because some clinics have private parking lots and limited public sidewalk space, the 35-foot zone essentially makes one-on-one conversations between activists and patients difficult if not impossible.

"This court [in the past] has held that the public sidewalks are a natural and proper place for free citizens to exchange information and ideas," said attorney Mark Rienzi, who is representing McCullen.

But Justice Anthony Kennedy said a government's responsibility to protect free speech and ensure public safety aren't mutually exclusive.

"In free speech cases, when you address one problem, you have a duty to protect speech that's lawful," he said.

The justices' decisions could affect the legality of similar buffer zones at funerals and places of worship.

The AFL-CIO, worried that a ruling to uphold buffer zones could make it more difficult for striking workers to picket outside their workplace, filed a brief in support of McCullen.

Lower courts have upheld the state law on the grounds it applied equally to all groups and thus doesn't discriminate against anti-abortion or pro-abortion rights activists.

Past Supreme Courts have ruled the First Amendment doesn't guarantee a person the right to express his opinions at all times and places, or in any manner that may be desired.

The high court three years ago ruled that the controversial Westboro Baptist Church of Topeka, Kan., could protest outside military funerals, provided it did so on public property. But justices left the decision of how far protesters should stay away from an event to local authorities. In the case, Westboro protesters said they abided by a police request to stay 1,000 feet away from the funeral.

The Supreme Court last took up the issue of buffer zones outside abortion clinics in 2000 when it ruled 6-3 in favor of a Colorado law that barred protests, the distribution of literature and other activity within eight feet of a facility.

Since then, four of the six justices in the majority have retired, while the three dissenters -- Kennedy, Scalia and Justice Clarence Thomas, remain on the court.

The Supreme Court prohibits protests and demonstrations on its grounds but allows for such activity, with conditions, on adjacent public sidewalks.