Cambridge Analytica, a UK-based psyops firm, with state of the art algorithms, tricks Facebook into divulging the data of millions (for which it now faces fines). Bannon is vice president, working closely with Trump. Cambridge Analytica has meddled in the foreign affairs of other countries as well. It's one of these new technology PR = covert ops manipulation companies.
The dupe Americans, though told this story (free press!) are Pavlovian creatures, trained to snarl and show fangs when Russians are mentioned, but flip over and show their cute tummies if ever a Brit needs a pet. So even though Trump overtly colluded with a foreign power, the FBI carefully said nothing about it. The story was 100% redacted from the Mueller report.
Congratulations Americans! You've fooled yourselves again. Lincoln was right about you (before the Brits had him snuffed).
