COLUMBUS, Ohio (WCMH) -- Ohio's race for U.S. Senate is considered to be among the most crucial in the country, but why is it so important? On Nov. 5, voters across Ohio will pick between incumbent Democratic Sen. Sherrod Brown and Republican businessman Bernie Moreno in a tight race. The Election Day matchup for the seat opposite Sen. J.D. Vance, former President Donald Trump's running mate, could decide which party holds control of the Senate for the next two years. The race is one of the most expensive nationwide, with donations coming in from all over the country. Some of the funders have interests vested less on party lines and more on the candidates' policies, like a pro-cryptocurrency group committing millions of dollars to ads in support of Moreno's campaign. OpenSecrets, a nonprofit government transparency group that tracks money in politics, lists Ohio's Senate race as the most expensive in the country for outside spending, at $125.7 million, and total spending, at $192.9 million. However, Quartz reported Montana's similarly high-stakes Senate race was outpacing Ohio, with campaign funding on track to hit a total of $250 million. OpenSecrets has also tracked the contentious Michigan Senate race as receiving more than $75 million in outside spending. All of that money is coming in as both parties fight for control of the chamber. As it stands, the Democrats hold a 51-49 majority. That includes three senators who are technically independents but tend to vote with the Democratic Party. However, 34 of those Senate seats are up for grabs in November. The Cook Political Report, an independent and nonpartisan newsletter covering elections and campaigns, has assessed all seats up for election. It said that of the 11 seats held by Republicans, all are expected to remain in Republican control. However, of the 23 seats held by Democrats, or Democratic-leaning independents, two are expected to flip Republican, with another two considered toss-ups. Sen. Joe Manchin of West Virginia used to be a Democrat before leaving the party in May and registering as an independent. Despite this, he still mostly aligns with the Democrats and votes with them on a lot of legislation. He is not running for reelection, and his seat is expected to go to a Republican. Other Democratic seats that are most at risk of flipping include Michigan, Montana, and Ohio. Depending on the outcomes in Michigan and Montana, or barring a surprise in another state, the Election Day bout between Brown and Moreno could be the deciding factor in whether or not Republicans take a majority in the senate. Currently, Brown is a slight favorite over Moreno, but only by a thin margin. Additionally, if Trump were elected president, Vance would have to leave his Senate seat as he takes on the role of vice president. That could leave another open spot in the senate, which would be appointed by Gov. Mike DeWine before going to a special election on Nov. 3, 2026. The governor would almost surely appoint a Republican, but the seat would be open two years earlier than expected, which could lead to further drama down the line.