In the climactic scene of Sylvester Stallone's new movie, "Cobra," the hero impales the villain on a giant hook and watches him writhe in agony as he's carried off into a flaming furnace. Then all that remains is to punch out the irritating liberal wimp in rimless glasses who has been popping up between orgies of bloodletting to condemn violence. The movie ends with the message: "Patrons are warned not to imitate any of the stunts and actions in this film."

Meanwhile, the Attorney General's Commission on Pornography is about to issue a report asserting that there is a "causal relationship" between pornography and violence. The commission has been entertaining the nation for the past year with its struggles to reach this preordained conclusion. A witness testified that the accidental discovery of a deck of dirty playing cards caused him to start stealing Playboy magazines and sexually abusing the family dog. Social scientists whose studies the commission has cited in support of its thesis have rushed to deny that their studies prove any such connection.

No strained evidence or reasoning is needed in the case of "Cobra," which directly advocates violence, glamorizes its practitioners and sneers at those who oppose it. The story line, in which Stallone is a rogue cop and his victims are wanton criminals, is merely the thinnest veil over the pornography of violence. In fact, the movie's "moral" -- that society is too easy on criminals -- is as artificially attached to "Cobra" as the laughable sermonettes sometimes included in sexual porn movies to give them the legally required "redeeming social value."

The movie's hypocrisy is brazen: the bloody violence of the bad guys is, if anything, more lovingly depicted than the bloody violence of the good guys. The nonsensical plot and token characterization (also reminiscent of traditional porn) are further evidence that the movie's only purpose is the depiction of violence.

The attorney general's commission recognizes that the government cannot outlaw pornography, but it plans to "condemn" the distribution of magazines such as Playboy and Penthouse and to offer guidelines for citizens groups wishing to bring pressure on distributors. The executive director of the commission has already written to leading magazine outlets -- on Justice Department stationery -- to announce that "the Commission has received testimony alleging that your company is involved in the sale or distribution of pornography." The ostensible purpose was to give these companies an "opportunity to respond." The effect, obviously intended, was that 7-Eleven, People's Drugs and other large chains announced that because of the commission's "evidence" they would no longer carry Playboy, Penthouse and similar publications.

I marvel at the cognitive dissonance that allows the administration to explore uncharted passages around the First Amendment in search of ways to stifle Playboy and Penthouse -- ostensibly because of some connection to encouraging violence -- while outright embracing Sylvester Stallone. Stallone has been to the White House at least twice. Last October he was seated with Nancy Reagan and the guest of honor at a state dinner. Earlier, he attended a special White House screening of "Rocky III."

President Reagan has virtually endorsed the Stallone cult of violence. "After seeing 'Rambo' last night, I'll know what to do next time," he said a year ago at the conclusion of the TWA hostage crisis. And: "Go ahead. Make my day," exploiting the only slightly less violent Clint Eastwood cult to fend off calls for a tax increase. Eastwood is another regular White House visitor and has been appointed to a presidential arts commission.

Attorney General Ed Meese has declared grandiosely that his porn commission "reflects the concern a healthy society must have regarding the ways in which its people publicly entertain themselves." The "purpose of a democracy involves not simply the functioning of its political system but also the achievement of . . . the good society." In other words, the government should concern itself with the nation's general moral tone -- a defensible view, though an odd one coming from an administration that also moralizes regularly about getting the government off people's backs.

It's one thing for political leaders to use the bully pulpit to help set a healthy moral tone. It's another thing for the government to impose its ideas of private morality on unwilling citizens. That's what's ominous about the porn commission's designs to make Playboy less accessible. What makes this exercise in quasi-censorship especially odious is its obvious insincerity. If the problem is violence, where are the Reagan administration's noncoercive tone-setting efforts? Which purveyor of public entertainment is doing more to promote violence, Hugh Hefner or Sylvester Stallone? But which one gets invited to the White House?