Haven't studies conclusively shown that violent images cause violence?
No, not conclusively. One scholar who analyzed about 200 recent studies of media violence said none provided support for the existence of a cause-and-effect relationship between violent imagery and actual violence. Japanese and Canadian TV programming is more violent than American TV, but those societies have much lower violent-crime rates than the United States.
Can violence on television be legally regulated?
Courts have generally said that it cannot be restricted without a violation of the First Amendment protection of free speech.
Isn't it unconstitutional for the government to force TV producers and viewers to use V-chips?
There is no mandatory V-chip system in effect, and the constitutionality of such a regulatory scheme has not been tested. What is in place now has been agreed to by the television networks. But it is true that television broadcasters may feel a threat of government regulation lurking behind even "voluntary" programs.