It's easy to understand why many in D.C. assume that control of the House and Senate will change hands in 2024. First, there's the math. Senate Democrats, who have a one-seat majority, are defending 23 seats, including three in states Donald Trump easily carried. House Republicans are trying to hold onto their slim five-seat majority while protecting 18 incumbents sitting in districts carried by Joe Biden, including five districts Biden won by double digits.