When the Supreme Court ruled for Citizens United in early 2010, it was largely seen as opening the floodgates for untracked money, including corporate gifts, into presidential races.
The ruling was especially significant for Hillary Clinton, as the challenge to the FEC was over small non-profits being able to pool whatever money to create DIY attack ads on... (drum-roll please)... HILLARY!!!
Of course the FEC still maintained some control over the process, as PAC money can't be directly coordinated with the candidate - an arm's length relationship must be maintained.
HA HA HAAAAAHHHH HHEEEE HEEE GIGGLE KERPLAT SNICKER GUFFAW WHEEEE HAWWW WE BE HAVING SUM FUN NOW!!!!!! PANT PANT PANT....
Sorry, I'm back. Yes, that's what the law claims.
Now check out the "arms length" relationships for just 1 such PAC, the eponymously named "Make America 1 Again", aka "Defeat Crooked Hillary" or "Keep the Promise I"...