That is why I suggest that all political contributions be ANONYMOUS. You can't sell influence if you don't know who is buying. Americans should be permitted to donate any amount they wish to any party or candidate they choose; that is FREEDOM. But purchasing an outcome for the donation makes it BRIBERY, a criminal act.
It’s a knotty problem. Individuals would be glad to give anonymously.
Big donors and corporate donors will find a wink wink nod nod way of letting the candidate know & collecting their markers after election.
It is like states with strict gun control and lots of illegal guns. Driving things underground means the criminals are well situated to control the action.
Even if one prohibited Corporate donations there would be a way to pass along value, book deals, seminars etc, stipends for giving talks..etc.
The worst part of the current situation is the sums of money controlled by the leftist billionaires. They can quite literally buy an election. I see it as a hobby for them like horse racing or Warhammer, exciting, challenging, requiring planning with lots of “bought” allies to stroke their egos and stoke their commitment to the leftist cabal. They see themselves as controlling the world, what a rush! They are also not very well socialized individuals tending to asocial personalities who do not empathize with others & see others as expendable or grist for the mill.
Maybe the solution is limiting both corporate & individual donations to much smaller numbers and including pacs and other revenue streams for candidates in that total amount. Lobbyists should not be writing legislature or buying Congress critters with any perks. The issues should be decided on the merit for the American people or to strengthen an industry as a whole. People are corruptible for surprisingly small sums of money.