Jimmy Carter: The U.S. Is an “Oligarchy with Unlimited Political Bribery”
theintercept.com
theintercept.com
Citizens United doesn't seem to be any sort of inflection point. The big jump was during the Bush/Kerry election, ironically the first Presidential cycle during which the 2002 campaign finance law ultimately struck down by Citizens United was in place. Spending actually went down during the Clinton/Trump contest, after the law was struck down, and Trump won despite Clinton spending almost twice as much.
Also, at this point most of the money can be spent outside the campaigns entirely. Robert Mercer can just run his simulations and use bots and paid posters to move public opinion around. He doesn't need to work directly with the campaign at all.
In presidential elections the Democrats tend to tie or outspend the republicans, for congressional and especially local elections they seem to fall behind.
Perhaps a better idea would be to have the voters decide on how much a senator should get paid after his term is completed. That might help keep them more true to their campaign promises.