Then he'd completely missed my original point that was about practical inability to prevent that exact scenario - "elect the next Manchurian candidate campaign run by the NSA". I do not think juducial review will enter the picture here. I am not sure what practical legal mechanism is available to prevent such scenario. I guess it would run the risk of being exposed by some whistleblower but with the latest developments in the area the chances are that it wont.
At this point I have doubts about who employs the Manchurian candidates in the first place, people behind the big companies or the three letter agencies. There are revolving doors between them.