evidence: Years prior, the court dealt another blow to the law meant to limit the power of wealthy individuals. In 2008's Davis v. FEC, the court struck down the Millionaire's Amendment, which allowed opponents of wealthy self-funding congressional candidates to bypass contribution limits. In recent cycles, self-funding candidates such as Sen. Rick Scott (R-Fla.) and Rep. David Trone (D-Md.) have found success. [...] Eight of the top 10 most expensive Senate races ever occurred after Citizens United with inflation factored in. With $213 million spent — including $97 million in outside spending — the hotly contested 2018 Florida Senate race is the most expensive ever. The 2016 Senate battle between Sen. Pat Toomey (R-Pa.) and Democrat Katie McGinty was blanketed by $127 million in outside spending. The candidates spent $53 million. [...] That's in contrast to the record numbers of Americans giving money to political candidates in the most recent presidential and midterm election cycles. High-profile candidates for Congress and the presidency rely on armies of small donors to fund their campaigns. But one check from a wealthy donor, such as 2020 Democratic presidential contender Michael Bloomberg's record $20 million gift to the liberal Senate Majority PAC, could effectively neutralize the efforts of thousands, even millions, of small donors.