The Lethal Weapon buddies are L.A. policemen Riggs and Murtaugh, played respectively by Mel Gibson and Danny Glover. In the just-released Lethal Weapon 4, Gibson's character has evolved from a nothing-to-lose nut, mourning the death of his wife, to a sweet-natured bad cop with a live-in girlfriend and a baby on the way. Meanwhile, Glover's Murtaugh, who was constantly repeating the mantra, "I'm getting too old for this shit," has become addicted to rushing out on his imperiled family so he can participate in a high-speed chase or terminate a lackey with extreme prejudice.

Lethal Weapon 4 is ostensibly about Riggs and Murtaugh's attempt to thwart a Chinatown crime boss who's smuggling in his countrymen and exploiting them as slave labor. More than ever, though, the story is an afterthought--an excuse for the leads to do their shtick while Joe Pesci (reprising his role as nattering Leo Getz) and Chris Rock (as a hilariously profane young cop) babble away on the edge of the frame. What's more, three previous films have added so many subplots that the only way to resolve them all is to have Riggs and Murtaugh shout lines like "Your wife is pregnant!" while emptying a clip into some random criminal. Even with the economizing, Lethal Weapon 4 dawdles for an hour--45 minutes before the actual plot begins, 15 minutes after it's resolved--to give every minor character ample time in the spotlight.

The series has also been getting increasingly surreal, heightening its violence and physical comedy until the two have become confusingly intertwined. Some lowlights from previous installments include the scene in Lethal Weapon 2 in which Murtaugh repeatedly riddles some henchman with a nail gun and then says (ha ha) "nailed the sucker"; or the scene in Lethal Weapon 3 in which Riggs and Murtaugh, demoted to beat cops, physically assault a jaywalker. The running "gag" in the fourth Lethal Weapon is how callously the partners knock off skulking Chinese thugs.

What makes the relentless, ridiculous violence of the Lethal Weapon movies that much odder is Richard Donner's habit of sneaking liberal humanist messages into his films. Through posters and dialogue, Donner has tackled dolphin-safe tuna, apartheid, abortion, gun control, the heartless U.S. immigration policy, and animal rights. All the while, though, his films treat human beings as disposable evil machines to be slaughtered indiscriminately.

Still, as appalling as Lethal Weapon 4 can be, there's something about it that's almost...quaint. The state of the art has changed, and films like LW4 and Armageddon seem archaic compared to John Woo's pop opera Face/Off or Jackie Chan's kinetic kung-fu comedies. Donner nods to the new bosses by casting Hong Kong martial-arts master Jet Li as his primary bad guy, and by employing visual references to Woo's gun-in-the-face poses and to Chan's outlandish stunts.

The problem is that the audience gets so charged up by the Hong Kong-inspired stuff that it makes the standard Donner action scenes seem all the more tired. My wife and I started chanting "Go Jet Li!" every time he appeared onscreen, and we mourned his requisite impaling at the end. (This isn't spoiling any surprises--the price of being a cool bad guy these days is a good impaling.) As for Donner, Gibson, and Glover, they really are getting too old for this shit. I think we all are.