9. Lt. Frank Drebin - The Naked Gun Series
Given that the guy managed to charm Priscilla Presley into becoming his wife, I guess it's sort of understandable that someone as likeable as Lieutenant Frank Drebin might be able to fall through the cracks somewhere as a lowly beat cop, but a
lieutenant? Really? The guy manages to get his oar in on some ridiculous undercover stake-outs that are surely reserved for the best agents, and through his constant failures and misinterpretations of the facts, manages to somehow "fail upwards", always solving the case by day's end. There's a lot to be said for the fact that he's also working with other klutzes like O.J. Simpson and George Kennedy, but Drebin is easily the dumbest of them all; maybe his superiors just keep him around because he's such a laugh (not that "sexual assault with a concrete dildo" needs any help being funny).