 Mill, for example, is an opponent of paternalism generally, but he does believe there are certain instances when intervention is warranted. He suggests that if a public official is certain that a bridge will collapse, he can prevent a person crossing. If, however, there is only a danger that it will collapse the public can be warned but not coerced from crossing. The decision here seems to depend on the likelihood of personal injury; the more certain injury becomes, the more legitimate the intervention. Prohibiting freedom of speech on these grounds is very questionable for liberals in all but extreme cases (it was not persuasive in the Skokie case) because it is very rare that speech would produce such a clear danger to the individual.