Congress in the Balance: House Leaning Blue, Senate Likely Red

Based on current polling numbers, it’s difficult for Democrats to win the Senate, as they must secure victories in red states such as Montana and Florida. However, the lower house of Congress is more attainable, with the current generic congressional ballot showing Democrats outperforming their 2022 numbers by multiple points, meaning they are likely to take back the House of Representatives.

The latest poll on the Generic Congressional Vote, conducted by The Economist/YouGov Sept. 15-17 with 1445 registered voters, found that Democrats had a 4-point lead. In the RCP Average for the Generic Congressional Vote, Democrats currently lead by two points, similar to Harris’ current 2.1-point lead in the Nationwide RCP Average.

Congressional polling is less detailed than other races that are conducted statewide due to the larger number of races – 435 House races each cycle compared to 33-34 Senate races. Only a few House races have a handful of publicly available polls every election cycle.

The generic congressional ballot is a good indicator of which party will hold a majority in the House, as the RCP Average of polls has accurately predicted the majority party in the House in every election since 2012, except for 2016. In 2016, the RCP Average had Democrats up 0.6 points before the election, but Republicans won by 1.1 points on average and secured an over 50-seat majority.

Focusing on the 2024 election, the current RCP Average reflects a 4.5- to 5-point swing toward Democrats compared to 2022, when Republicans led by 2.5 points in the RCP Average for the Generic Congressional Vote and won by 2.8 points in aggregated House election totals. This 5-point swing could be critical, as in 2022, 40 House races were decided by 5 points or fewer. Of those, 18 were won by Republicans.

At the start of the Congress elected in 2022, there were 222 Republicans and 213 Democrats. This means if Democrats could flip just five seats, they would regain a majority. Based on the difference between the 2022 elections and current polling, they are expected to flip more than five seats and take a majority in the House. 

If Democrats do flip the House, it would mean a split Congress, as the Senate is likely to flip back to Republicans in the November elections. Currently, the Senate is controlled by Democrats with a 51-49 majority. However, with the retirement of West Virginia Democrat Sen. Joe Manchin, who held the seat as a moderate Democrat in a deep red state, the Senate would be tied at 50-50.

The likely tiebreaking race will be in Montana, where incumbent Democrat Sen. Jon Tester is trailing his Republican opponent Tim Sheehy in the RCP Average for the Montana Senate Race by 5.2 points. Despite other Democrats leading in Senate races in swing states, including Ohio, losing these two states would likely result in Republicans taking the Senate.

A possibility for a split Senate exists if Democrats can pick up the Florida Senate seat, where former Democratic Rep. Debbie Mucarsel-Powell is challenging Republican incumbent Rick Scott. The current RCP Average for the Florida Senate Race has Scott up by 4.3 points, but the latest The Hill/Emerson poll, taken earlier in September, had Scott up by only one point, indicating there’s a chance Mucarsel-Powell is gaining and could win the seat.