The financing of electoral campaigns in the United States happens at the federal, state, and local levels by contributions from individuals, corporations, political action committees, and sometimes the government. Campaign spending has risen steadily at least since 1990. For example, a candidate who won an election to the U.S. House of Representatives in 1990 spent on average $407,600 ($980,896 in ) while the winner in 2022 spent on average $2.79 million ($3.00 million in 2024); in the Senate, average spending for winning candidates went from $3.87 million ($9.31 million in 2024) to $26.53 million ($28.51 million in 2024).
In 2020, nearly $14 billion was spent on federal election campaigns in the United States — "making it the most expensive campaign in U.S. history", "more than double" what was spent in the 2016 election. Critics assert that following a number of Supreme Court decisions — Citizens United v. FEC (2010) in particular—the "very wealthy" are now allowed to spend unlimited amounts on campaigns (through Political Action Committees, especially "Super PACs"), and to prevent voters from knowing who is trying to influence them (contributing "dark money" that masks the donor's identity). Consequently, as of at least 2022, critics (such as the Brennan Center for Justice) allege "big money dominates U.S. political campaigns to a degree not seen in decades" and is "drowning out the voices of ordinary Americans."