Bradhadair said:
6 months is a long time for clearance.
Actually, it might not be, depending on what you're being cleared for and the level of the clearance. Some levels of clearance require in-depth investigation and interviews. However, because Vaughn held a clearance before, the process should go more quickly. But Vaughn didn't necessarily have to have a high-level security clearance to talk to Sydney. He knew the basic facts already and the only fact that he was learning was that she had been found alive. They apparently didn't fill him in on what had happened to her father, for example. So he really wasn't a heck of a lot of help to Sydney--and I'm not sure how helpful he could be to the CIA, either (perhaps it was that he served as her handler). They should have sent Weiss (since Dixon was probably too busy with divisional matters).