Senate campaigns in 2020 cost over $1.1 billion and included nine of the top 10 most expensive campaigns ever — a jaw-dropping amount that promises to only go up in 2022.

This trajectory was best epitomized by the two Georgia runoffs that gave Democrats control of the Senate in January. The four candidates in the two races raised nearly $500 million (much of which isn’t included in the $1.1 billion figure), making the campaigns by far the most expensive Senate races ever.

Responding to targeted and persistent online fundraising appeals, donors from across the country poured millions into the candidates’ coffers, a phenomenon not unique to Georgia as donors try to influence which party controls Congress, according to Ian Vandewalker of the Brennan Center for Justice’s Democracy Program.

Yet, as stunning as the sums raised by the individual candidates are, those contributions are only part of the cavalcade of cash that poured into Georgia. According to calculations by the Center for Responsive Politics, “outside spending” — expenditures made independently of the candidates but spent to support or oppose one of them — totaled another $430 million. When added to candidate spending, this figure means the Georgia runoffs were a nearly $1 billion proposition.

While campaign cash has long fueled elections — the California Democratic power broker Jesse Unruh is credited with calling money “the mother’s milk of politics” — outside money, spent independently of candidates, began to take on an outsize role only 40 years ago. The result has been more ideological parties, incessant fundraising, an explosion of campaign spending and less functional governance.

The concept of the political action committee dates to the 1940s. Ironically, however, the number of PACs grew only modestly until the early 1970s when Congress, prompted by the exposure of political money scandals linked to Watergate, placed limits on campaign contributions and spending. Those efforts were dealt a major blow by a 1976 Supreme Court ruling — Buckley v. Valeo — in which the court held that government restrictions on independent expenditures were an unconstitutional infringement of free speech.

A brash, aggressive group of young New Right activists pounced on the opportunity created by Buckley and began to raise and spend unlimited amounts of money. By 1980, using a sophisticated, targeted direct mail fundraising strategy the National Conservative Political Action Committee (NCPAC) had raised millions to target a handful of incumbent Senate Democrats. NCPAC’s success with independent expenditure campaigns, deployed in the form of angry, grievance-driven attack ads — branding targets “traitors to their country” or “baby killers” — surprised even its founders, who were refreshingly candid in acknowledging the risks involved with such efforts.