WASHINGTON — The First Amendment is strong medicine, the Supreme Court keeps telling us, and it even requires vulnerable people to listen to things they do not want to hear.

Chief Justice John G. Roberts Jr. explained this in 2011 to the father of a fallen soldier who had to endure a hateful protest while he tried to lay his son to rest. The First Amendment, the chief justice said, protects “even hurtful speech on public issues to ensure that we do not stifle public debate.”

In June, Chief Justice Roberts told women seeking abortions essentially the same thing in a decision striking down buffer zones around clinics in Massachusetts. “Vital First Amendment interests,” he said, required women to hear from opponents of abortion in the fraught moments before they entered those clinics.

But the Supreme Court’s devotion to the First Amendment has its limits. It stops at the edge of the grand marble plaza outside its own courthouse.