You are mistaken. The voters are in charge, the voters are in control. They just use their votes poorly.
The true currency of politics is votes, not money. And since the system is one person one vote, the 99%s are in charge. If a candidate fears that a significant number of voters will vote against him if he supports a corporation on a particular issue then he will side with the voters not the corporation. Above all things, politicians desire re-election. They will only server corporations to the extent that it does not jeopardize their re-election, in other words to the extent that the voters allow.
Irregardless of corporate donations, voters could establish control by punitive voting. The voting out of office of a politician who too often sides with corporations over voters. No passes because of party or position on some other issue, just always voted out if siding too often with corporation. That will create a Darwinian effect that caused politicians to fear and be more responsible to voters.
The biggest trap for voters in the U.S. is party loyalty. Being a member of a party is fine, but automatically voting for your party candidates makes you irrelevant. You are irrelevant to your party because they already have your vote, you are irrelevant to the other party because they can not attain your vote. The only voters who matter in the U.S. are independents and those Dem/Rep party members who are willing to break ranks and vote for candidates other than from their party.