Injunction Preventing Protesters From Approaching an Individual Entering an Abortion Clinic

This spring the United states Supreme Court will review the constitutionality, under the First Amendment guarantee of free speech, of an injunction, issued by a federal court in Buffalo, New York, directed at anti-abortion protestors conducting demonstrations at abortion clinics. The injunction allows protestors to approach a person heading for the clinic, but requires them to step back fifteen feet if the person indicates that she or he doesn't want to talk to the protestor. The antiabortion protestors argue that the injunction violates their right of free speech. The abortion clinics contend that the injunction doesn't violate the protestor's rights, especially in light of, what the abortion clinics term, "the unrelenting campaign of harassment and intimidation" waged by the protesters. Does the injunction violate the anti-abortion protestors' right to freedom of speech? If so, why? If not, why not?