You know you’re in trouble when the best thing about a movie is William Shatner. You know you’re in even more trouble when the best things William Shatner does in the movie in question you’ve already seen in the film’s trailer. And that’s every inch the case with Showtime, a movie that sets out to prove that a comedy needn’t be about horny teenagers in order to be lame … and succeeds with a vengeance. It’s not so much that Showtime is bad — though it isn’t very good — it’s that it’s just so mind-numbingly ordinary. The idea apparently was that Robert De Niro and Eddie Murphy would make a good screen team. And they probably would be, if they were in a better movie. The pair do have a certain chemistry, even if De Niro looks even more like a harried actor in search of a paycheck than he did in The Score. (Where is this man’s career sense? How many mortgages is he paying off?) Plus, Murphy has abandoned the whimsy of Shrek and the avuncular charm of Dr. Dolittle 2 to pretend he’s still the 20-something wiseacre of 48 Hours and not the 40- year-old comedic actor of reality. As it is, the degree to which Showtime works as a film is completely dependent on the two. God knows, its appeal doesn’t lie in its screenplay, which attempts to spoof the mismatched cop-buddy syndrome without realizing that the syndrome it’s spoofing wasn’t taking itself seriously in the first place. Regardless of that, you’d think even the rankest of amateurs would realize that you don’t become the thing you’re spoofing, which is what happens here. It’s not so much that Eddie and Bobby make fun of Mel and Danny in the Lethal Weapon franchise as they simply try to become them. De Niro is Mitch Preston, a savvy veteran detective who is forced to star in a reality-based cop show so that the TV network won’t sue the LAPD for $10 million over Mitch shooting out TV camera. Naturally, the producer (Rene Russo) wants him to have a partner — “maybe a funny ethnic type” — and this, of course, turns out to be none other than Murphy as Trey Sellars, a loudmouthed hotshot who has twice failed the detective exam and who moonlights as an actor. Equally naturally, it’s loathe at first sight and predictability follows at an alarming rate. The only marginally new thing offered by the screenplay lies in the digs it gets in at television’s idea of “reality”: Rene Russo redecorating the police department to look more like what she thinks a police department ought to look like, hiring William Shatner (on the strength of his T.J. Hooker series) to coach De Niro and Murphy in how to look like cops, etc. This part of the film is mildly funny, but it’s not exactly the height of satirical revelation to suggest that there might be a gulf between TV reality and the standard-issue kind. Overall, the movie’s a mess, as well as being utterly superfluous. A fair barometer of this is indicated by the fact that the ubiquitous outtakes at the end of the film are virtually indistinguishable from the movie itself. There are worse ways to kill 90 minutes, I suppose, but whether you have 90 minutes that need killing is another question.