Citizens United was not about, and did not change, the restriction on "candidates receiving donations from companies", which is what OP was discussing.
Considering the maximum campaign contribution is $2,700 per candidate, I think it's safe to say they plan on influencing the election without relying on directly funding candidates. That does not mean that the candidates aren't responsive to these alternative funding streams.
Another example of how this money corrupts the position of politicians can be seen in the Clinton Foundation.
"Giustra is a Canadian mining magnate who became a large donor for the Clinton Foundation 11 years ago, going on to set up the ‘Great White North’ chapter of the foundation. He currently sits on the board.
The billionaire later became an example of the foundation’s murky ties between donors and apparent political favors, due to the 2005 dinner with Giustra, Bill Clinton, and Kazakhstan president Nursultan Nazarbayev – and the deal that “stunned the mining industry, turning an unknown shell company into one of the world’s largest uranium producers in a transaction ultimately worth tens of millions of dollars to Mr Giustra,” wrote the New York Times, quoting analysts."
> You have to look more broadly than just direct contributions to candidates
No. Citizens United only covered direct contributions to candidates, and while it is correct that you should look more widely to ascertain the overall workings of the American electoral system, the second you do so you are no longer evaluating the impacts of Citizens United.
> Consider the Koch brothers [...] Giustra is a Canadian mining magnate who became a large donor for the Clinton Foundation
You are now talking about independent expenditures by individuals, which ALSO was not impacted by Citizens United. Neither example you give is something which was illegal prior to Citizens United, but legal afterwards. (And in fact, one of the examples took place before Citizens United, so um...)
As a result, your post just underscores how unimportant (and overhyped) Citizens United was, once you "look more broadly than just direct contributions to candidates".
