With the eminent return of 24, one of the more important and well-produced shows of the new century, now would seem to be a good time to revisit one of the most famous, and unfortunately overplayed cards in recent TV history---- the double-agent or mole.
As I once joked to a fellow viewer of the show, I would never want to work at CTU because they seem to have the least effective security clearance procedures in government history--- every season, there would appear to be a double agent working against the government. Because it worked so brilliant in it's premiere season--- the revelation of Nina Myers as a double agent is one of the great twists in television history, they began to play that card far too often as the series progressed. Soon other law enforcement based dramas, such as The Mentalist and Castle would become known for having trusted officers be pawns for shadowy operatives.
Howard Gordon seems to have taken a completely different approach with his next major series Homeland. In season 1, it became clear very quickly that there was a mole operating within the CIA. In Season 2, even though Abu Nazir was operating as though with intel he couldn't have gotten from anywhere else, no one on the show seemed very interested in obtaining the mole's identity. At this point, it seems like the writers have completely forgotten this story arc, and if they choose to pursue it in Season 4, I doubt that there are any viewers left who will care.
In recent years, other series have tried the same gambit. Last season, Scandal, which moves at such an accelerated pace that it's hard to keep track of it, devoted it's back half to trying to find a mole in the intelligence network. The problem was, when they finally identified him in the second season's penultimate episode. he was a character forgotten since the first season finale, who had been presumed dead. By that point, who cared?
In the past few weeks, two other series have dealt with the idea of sleeper agents and moles within the government, and seem to be taking it to extremes. On The Blacklist, the world seems to be filled with double agents--- we have found secret agents within the FBI, the government, and, in the case of Elizabeth Keene, her own husband has been revealed to be a double agent for--- well, the series doesn't seem to want to explain that one. On Marvel's Agents of SHIELD, in the space of two episodes, a central character was revealed to be a mole for Agent Fury. Then it was revealed that half of SHIELD was under the operation of an organization called HYDRA (check your comics), including in the denouement, Agent Ward.
The idea that no one can be trusted is an effective idea, but the real problem with it, the less you trust someone, the harder it is to form an attachment to them as a character. This was one of the fundamental flaws of The X-Files, and 24 followed it to the point of lunacy. The problem is, if you put everybody as a potential double agent, it gets really hard to care about them, or whether they live or die. There's paranoia, and then there's just plain laziness. My advice to Gordon: this time around, try to have somebody we can trust besides Jack Bauer.