Most expensive race - South Carolina
The South Carolina race between Republican incumbent Lindsey Graham and Democratic challenger Jaime Harrison is the most expensive Senate race in history. Harrison raised an astounding $107,568,737 while Graham raised $72,690,495 — but it wasn’t enough to overturn a Republican stronghold where Black voters, in particular, have long been targets of voter suppression.
The correlation between money and likelihood of winning is also affected by who is donating and why they’re motivated to do so. About 53.6% of Harrison’s campaign funds (over $57 million) came from individual small donors, meaning people who donated $200 or less. “When you're doing [small donations], you're not necessarily doing it because you think that your $25 donation is going to tip the balance,” says Bryner. “It's a case of people wanting to get their voice heard and wanting to do what they can.”
After the passing of Justice Ruth Bader Ginbsurg on September 18th, fears of a conservative justice filling her seat led to a surge of donations. Within a day of Ginsburg’s death, over $71 million had been raised for Democratic campaigns. It was an expression of enthusiasm and frustration — not a bet on the likeliest winners, not a reflection of who would be voting in this race. With 99% of votes reporting, Graham has 54.5% and Harrison has 44.2%.
“The other thing, though, is that it's only been very recently that we've seen this major small donation uptick,” says Bryner. “It's forcing a lot of us to rethink campaign donations. In the past, one of the biggest roadblocks to challengers was money. And right now we're finding that, well, money can be a roadblock.” But it’s not the only one. “There's a diminishing return.”
After his win, Graham showed confidence in a Trump win, saying, “To all the liberals in California and New York, you wasted a lot of money. This is the worst return on investment in the history of American politics.” Later, he announced he was donating $500,000 to Trump’s Official Election Defense Fund.
Second most expensive - Arizona
Republican incumbent Martha McSally raised $55,772,809, but Democrat Mark Kelly — ex-astronaut and husband of former Arizona representative Gabby Giffords — outraised McSally with $88,856,406. In August, McSally joked that supporters should skip a meal to make an extra contribution to her campaign. In 2017, the Cook Political Report’s Partisan Voting Index (PVI), which measures how strongly a state or district leans Republican or Democrat compared to the rest of the country, showed Arizona leaning R+5 — five percentage points more Republican than the national average. But the Cook Political Report this year had Arizona’s senate race and electoral votes leaning blue. Kelly has been called the winner with 51.2% of votes right now, compared to McSally’s 48.8%.
Third most expensive - Kentucky
Incumbent and Senate Majority Leader Mitch McConnell raised $55,500,677, while Democrat Amy McGrath raised $88,098,919. McGrath’s campaign also received a flood of donations after Ginsburg’s death — a fund called Get Mitch Or Die Trying split donations between Democratic Senate races. But the Cook PVI rated this race as likely to go to McConnell. Bryner reminds us that in most of the Senate races, the outcome was ultimately in line with expectations. “People focus on the aberrations — I don't think that Kentucky ever should have been a surprise to anyone,” she says. “I don't think that Texas should have ever been a surprise to anyone. There's nothing here that should be surprising to people who study those states. I think that it's this motivation from activists — on the left, mostly, but also on the right — to nationalize what are essentially state elections.”
Ultimately, McConnell received about 57.8% of votes, and McGrath got 38.2%.
Fourth most expensive - Maine
In the Maine senate race, Republican incumbent Susan Collins won, having raised $26,511,555 while her Democratic opponent Sara Gideon raised $68,577,474. Cook had this race as a toss-up, and though Gideon raised about 2.5 times what Collins did, Collins won about 51.1% of votes. Because Maine has ranked choice voting, if Collins had received 50% or less of total votes, the candidate with the least votes would have been eliminated and the second choice of voters who preferred the eliminated candidate would have been added to the count.
Fifth most expensive - Michigan
In a race that Cook determined as Democrat-leaning, incumbent Gary Peters (D) raised $42,543,692 while Republican John James raised $37,131,873. Peters kept his seat, but it was a close race, with Peters getting 49.8% and James getting 48.3%.
