OK this might seem like a real dumb question, like if I don't get this I don't get the movie but let's ignore that for just a second. I realize that this would be the most basic part of understanding the plot, but was Jason sent by Carver & the DEA to build (the so-called) John Hull up into the drug trade??
No definitely not! Jason (Goldblum) was not in any way aware of John's DEA involvement/employment until the very end. Seems to me Carver's "God complex" had more to do with a plethora of informants and crooked cops feeding him information about Hull's every move, and less to do with any connection to Jason. I dont think there's any possibility the two of them (Carver and Jason) could have possibly been "in league", especially after Eddie got Hull pinched, Hull didn't talk to the cops, and Jason got his case dismissed instantly, then rewarding him by moving Hull up in the organization (replacing Eddie the snitch). If Hull hadn't proven his loyalty after getting caught there's no way Jason or anyone would have trusted him with their business and trade secrets. Also if you remember the substance Jason gave Hull at first was baby laxative, not cocaine. If Jason was in on the undercover operation with Carver there would be no reason to go through all that, he would have just given him the real thing and vouched for Hull to his boss, Felix Barbosa.
Make sense?
As you can tell I love this movie, and have seen it about ten times or so since it came out. I recently read in a book about film noir that this film is actually considered part of that genre, and I can finally make the link between it and what I have always considered to be classic noir films of the '40a and '50s.....Fishburne is really incredible in all his roles but here I think is his best performance, and the duality and conflicting nature of his character is really done justice IMHO....definitely one of those films you can watch again and again through the years...