Note to self - separate row for each player at the start of the following notes
Loretta Lynch along with DAG/FBI/National Security Division Head used Russian lawyer Natalia Veselnitkskaya's planted social contact with Paul Manafort as an excuse to obtain a FISA warrant for Manafort and investigated him. Then Mueller prosecuted Manafort (convicted of financial crimes). The same DOJ staff obtained a FISA warrant for Papadopoulus, and investigated/prosecuted him (convicted of lying about his Russian contacts). They obtained a FISA warrant on Carter Page and investigated him (no conviction). The DOJ obtained a FISA warrant on General Michael Flynn and investigated/prosecuted him (no conviction).
This 'leap-frog' tactic was designed to encircle the DOJ's real target(s) (e.g., Trump campaign, Trump, supporters etc.) and collect communications which are private (supposed to be screened out of FISA surveillance). Support for this effort included UK intel; access to FISA data - upstream data collection and tangential contacts (umbrella survey); foreign target designators (e.g., foreign 'outside contractors' given 702 access indefinitely by the FBI).
UK assistance was used to navigate around barriers normally in place regarding FISA survellance. Such 'assistance' included a spy insert, an additional non-FISA warrant and a (classified) spec ops warrant
