Get a REAL job. When the cells aren't aware that they're working for the CIA, or think they're working for someone else, they can be put to other devious uses. For example, if the CIA controlled a cell which thought it worked for the PLO, they could send it on a terrorist mission with the intent that they be caught. This would have a two fold advantage for the CIA, first, the PLO would be blamed (providing a good opportunity for the U.S. government to expouse propaganda against the PLO), and secondly, it would allow the CIA to commit a terrorist attack with extremely little risk of exposure -- to achieve a greater level of interference in the affairs of foreign governments.