 There are other instances when the harm principle has been invoked but where it is more difficult to demonstrate that rights have been violated. Perhaps the most obvious example is the debate over pornography. As Feinberg notes in Offense to Others: the Moral Limits of the Criminal Law, most attacks on pornography up to the 1970s were from social conservatives who found such material to be immoral and obscene. This type of argument has died away in recent times and the case against pornography has been taken up by some feminists who often distinguish between erotica, which is acceptable, and pornography, which is not, because it is claimed it degrades, harms, and endangers the lives of women. The harm principle can be invoked against pornography if it can be demonstrated that it violates the rights of women. 