Why is campaign finance a concern in the united states?

Because we have a one-man, one-vote Constitution. So why should (for one example) Betsy Prince DeVos, who has only one vote, have an outsized influence on public policy?She has influence out of all proportion to her one vote because she’s extremely wealthy, can afford to donate to candidates she and her family favor, and she has said that they keep track of who receives their donations, and how they vote on the issues that matter to Betsy and her DeVos and Prince relatives.One thing they want is lower taxes because even though they have more money than they can spend, they’re still greedy. If the abortion that the Republicans call tax “reform” is actually passed by Congress and signed into law by President Trump, it will be because of megabucks donors like Betsy.If it is, it will benefit Betsy and her relatives, but it will not benefit the nation as a whole. No one on either side of the political spectrum should have that kind of influence.