Currently, the math favors Republican Senate candidates far more than Democrats, with the GOP only having to defend 11 seats compared to Democrats' 23. The most competitive Republican contests are in reliably red states, where Sens. Rick Scott (R-FL) and Ted Cruz (R-TX) are seeking their second and third six-year terms, respectively.

Democrats, however, are in a far more precarious position, with several senators in highly competitive races hoping to win another term in states where Trump won easily in both 2016 and 2020. Sen. Joe Manchin (D-WV) is not seeking another term, and Republicans are expected to easily win that seat given that the Mountain State went for Trump by double-digit margins in the last two elections.

This means that the GOP — which currently has 49 U.S. senators — could win back the majority by taking just one of the close contests in either Arizona, Montana, or Ohio. After Sen. Kyrsten Sinema (I-AZ) announced she would not be running for reelection, the Grand Canyon State's Senate race will be between Republican election denier Kari Lake or Rep. Ruben Gallego (D-AZ). Sen. Jon Tester (D-MT) is seeking a fourth term in November, and is the lone Democrat representing a statewide seat in the Big Sky State, which Trump also won handily in both 2016 and 2020.

Ohio's U.S. Senate race may be the most expensive, given the Buckeye State's wealth of Electoral College votes (17 in 2024), longtime incumbent Sen. Sherrod Brown's (D-OH) bid to keep his seat for a fourth term and the surprising result last year to permanently enshrine abortion rights in a now-comfortably red state that Trump won in both of his past campaigns. Ohio Republicans nominated Bernie Moreno in last month's primary, who has indicated support for a national abortion ban after 15 weeks of gestation.

Allison reported that the GOP has attempted to shore up its fundraising gap with Democrats by recruiting wealthy candidates who are able to invest large sums of their own personal wealth into their own campaigns. But GOP candidates are even trailing in those races with the exception of businessman Eric Hovde in Wisconsin, who slightly outperformed Sen. Tammy Baldwin (D-WI) in first quarter fundraising by loaning his campaign $8 million.

Businessman Tim Sheehy, who is running against Tester in Montana, is one example of that strategy in practice. The former Navy SEAL who launched his own aerial firefighting business has raised $8.3 million so far in the 2024 cycle, and has $1.9 million in cash on hand according to data compiled by Opensecrets. However, Tester is running up the score with more than $32 million raised and $12.6 million in cash on hand.

Trump's own legal woes could also be holding back the GOP from investing more in down-ballot races like the Arizona, Montana and Ohio Senate races. After his daughter-in-law Lara Trump was elected as co-chair of the Republican National Committee (RNC), the Trump campaign and the RNC entered into an agreement in which Trump's affiliated PACs — which help pay his legal expenses — get a cut of funds raised by the RNC before they actually go into the RNC's own accounts. The former president not only has two massive civil judgements adding up to a hefty nine-figure sum to contend with, but he is also having to pay to defend himself from 88 felony counts in three separate jurisdictions this year.