Special interest groups generally can’t “fund his re-election” because it’s illegal for corporations to donate to candidates. It might be worth considering whether your belief that “it happens all the fucking time” is based on facts or some sort of inchoate narrative you’ve picked up over the years.
> Can't they can give money to PACs which then give to candidates?
No, but they can sponsor a PAC, which frees up more of the money a PAC raises from individual sources for donations to candidates; this is different only if you ignore the fungibility of money.
(They can also spend directly or via a “SuperPAC” on advocacy that is for/against candidates but legally not coordinated with candidates, and SuperPAC activity in practice is often coordinated with campaigns via public signalling and other mechanisms.)
They can’t contribute to PACs either. PACs just pool individual contributions. They can give to SuperPACs, but SuperPACs can’t contribute to candidates.
The PAC are required not to coordinate and they can be scrupulous about never being in the same room as the candidate. But they don't need to coordinate to e.g. run a TV ad campaign endorsing a candidate who's done something they like.
They can hire the candidate after his term in office to 'consult', or give paid speeches, or lobby for then, or play golf all day. Or just cut a check to his charitable foundation, out of the goodness of their hearts. (A recent presidential candidate's family has hit four out of five of those.)
They can fund a PAC that either endorses, or opposes a candidate. The difference between funding their campaign directly, and funding a PAC that campaigns on a candidate's behalf is a fig leaf.
Tell me - in practice - how do these things differently from direct funding of a campaign?
