While most Americans are focused on the presidential race between Vice President Kamala Harris and former President Donald Trump, both major parties are eyeing key Senate and House races to see who will control the legislative branches of government.

There are several competitive down-ballot races in 2024, but these twelve are the most important to watch on Election Day.

The Senate is currently under Democratic control, but polling shows Republicans can take over if they win seats in Montana, West Virginia, Pennsylvania, Wisconsin and Ohio. The election prediction model from 538 shows Republicans winning control of the Senate in 916 out of 1,000 election simulations at the time of writing. Republicans only need to pick up three out of the five seats to flip the majority.

There’s now an 84% chance Republicans win back control of the Senate. pic.twitter.com/0lSU4H0btC

— Polymarket (@Polymarket) October 24, 2024

Montana:

Montana looks to be the most straightforward pick-up for Republicans. Three-term Democrat Montana Sen. Jon Tester is fighting off a formidable opponent, Republican Tim Sheehy. Montana is a deep-red state, and most polls show Sheehy has the advantage of beating Tester. Democrats and their friends in the corporate media have spent considerable time trying to help Tester over the line. Polling shows that Sheehy is leading Tester by 4 points, however, placing his numbers outside the Emerson College polling’s margin of error.

The latest polls show Tim Sheehy leading against incumbent Sen Jon Tester. Republicans can capture control of the US Senate if we win this race. Let’s go Montana!
pic.twitter.com/xhgOctUQ93

— Garbage Chad Prather (@WatchChad) September 14, 2024

West Virginia:

Democrat candidate Glenn Elliott, a former two-time Mayor, and Republican West Virginia Gov. Jim Justice are fighting for the state’s open Senate seat. Justice is very popular in the state and is favored to win the seat. The 538 election simulator found Justice with a 99% chance to win. The most recent polling from August shows Justice polling at 62% and Elliot at just 28%.

Pennsylvania:

Pennsylvania will be a harder pick-up for Republicans, and if Democrats lose, it will arguably be the biggest upset. Incumbent Democrat Pennsylvania Sen. Bob Casey and Republican candidate Dave McCormick are battling for the seat. Despite the 538 election simulator showing Casey beating McCormick 71 out of 100 times, his campaign has seemed nervous he’ll be able to win. In recent weeks, Casey has distanced himself from the Biden/Harris administration by running ads agreeing with Trump’s policies on the economy and immigration. After positive October polling, which gave McCormick a slight lead, November polling shows Casey has just a 2-point lead over McCormick heading into Election Day.

🚨 BREAKING: A new poll by Atlas Intel shows @DaveMcCormickPA in the lead for the first time in the Pennsylvania Senate race.

🔴 Dave McCormick 48.3% (+1.2)
🔵 Bob Casey 47.1%

(Atlas Intel was the most accurate pollster in 2020) pic.twitter.com/YB6ZsqOMxI

— Kyle Martinsen (@KyleMartinsen_) October 19, 2024

Wisconsin:

Recent polling shows that just two points separates incumbent Democrat Sen. Tammy Baldwin and Republican challenger Eric Hovde for Wisconsin’s Senate seat. This race will likely rest on whether Trump can win Wisconsin and bring up down-ballot races like Hovde’s, according to Charles Franklin, director of the Marquette Law School Poll. (ROOKE: Harris World Should Keep Panicking. She’s Floundering In Only Election Metric That Matters)

“If Trump were to win by several percentage points, that would be a real challenge for Baldwin,” Franklin said. “If it’s a single percentage point difference, like it has been for the last two presidential races, then I think it’s real tricky to know which way the Senate race goes.”

Ohio:

Ohio’s Senate race between Republican candidate Bernie Moreno and Democrat Ohio Sen. Sherrod Brown is neck and neck, according to new polling. Moreno holds a half-point lead over Brown. Still, 538’s election simulator has Brown beating Moreno 56 out of 100 times. Trump is expected to win Ohio, which could help push Moreno over the edge.

🚨 BREAKING: Ohio Republican Bernie Moreno now LEADS THE POLLS for Senate. pic.twitter.com/BchL2oTFVG

— Eric Daugherty (@EricLDaugh) November 4, 2024

Republicans currently hold a slim majority in the House, with Democrats only needing four seats to take control. The 538 polling simulator gives Republicans the advantage in holding onto power in the House, showing Republicans with a 58% chance to win. While there are several close House races, Democrats’ best chance at taking back the House likely rests in seven close seats in California, New York, Washington (state), Michigan and Alaska.

California: 

California is a deep blue state with 12 Republican-held seats, which party incumbents are fighting to keep. Trump’s successes in turning out to vote in red areas of California will be critical for these candidates’ abilities to win reelection. Democrats want to take California’s 22nd, 27th, and 45th Congressional Districts, where the margins between the parties are razor-thin.

Partisan polls show incumbent Republican Rep. Michelle Steel and her challenger, Democrat Derek Tran, within the margin of error to win California’s 45th Congressional District. While Democrats are hopeful Tran will pick up the seat, 538’s election simulator shows Steel with a slight advantage to win the race. (Democrats Working Overtime To Turn Election Conspiracies Into Reality)

For California’s 22nd district, Republican California Rep. David Valadao is fighting off Democrat candidate Rudy Salas. While Valadao could receive help from Trump via a down-ballot pick-me-up, he is not likely to receive any campaign assistance from the former president, whom Valadao voted to impeach. While October polling shows Valadao trailing Salas by two points, 538’s election simulator has Valadao favored to win.

New swing-state California polling!!

🔵 George Whitesides — 44%
🔴 Mike Garcia* — 43%

🔵 Derek Tran — 45%
🔴 Michelle Steel* — 43%

🔵 Rudy Salas — 43%
🔴 David Valadao* — 39% https://t.co/jSyenrL1rH

— Anthony Adragna (@AnthonyAdragna) September 24, 2024

Republican incumbent Mike Garcia is up against Democrat George Whitesides for California’s 27th Congressional district. Garcia first won his seat in 2020 after Democrat Rep. Katie Hill resigned. He beat Democrat Christy Smith in the March 2020 special race, in the November 2020 general election and then again in 2022. Garcia no longer faces Smith but rather a political newcomer, Whitesides. September polling from the University of Southern California/California State University Long Beach Center for Urban Politics and Policy/Cal Poly Pomona gives Whitesides a 2-point advantage over Garcia to win.

New York:

The rematch between incumbent Republican New York Rep. Marc Molinaro and Democrat Josh Riley has become the most expensive House race in this election cycle. Spectrum News reported that candidates have spent over $45 million to win the seat. October polling shows Riley with a 4-point lead over Molinaro and 538’s election simulator shows Molinaro losing to Riley 54 out of 100 times.

Survey USA poll for NY19

House
🟦Riley 46%
🟥Molinaro 42%

President
Harris 48%
Trump 47%https://t.co/IUPGwW3fbO

— Poll Tracker 📡 (@PollTracker2024) October 22, 2024

Washington:

The rematch for Washington’s 3rd Congressional district between incumbent Democrat Washington Rep. Maria Gluesenkamp Perez and Republican challenger Joe Kent puts Democrats on the back foot. They can’t afford to lose seats in their march to control the House. Still, Kent is the favorite in the race. Democrat-aligned polling has Kent tied with Gluesenkamp Perez, and 538’s election simulator shows Kent with a 55% chance of winning the race. If Republicans are going to pick up seats to expand their majority, Kent’s race against Gluesenkamp Perez looks promising.

Race to watch — Washington state District 3 – where the ballot bomber just attacked.

Joe Kent (R) is neck-and-neck in the polls with Congresswoman Perez (D). Right now both polling at 46%.

WA D3 is a swing district and Perez won it in an upset in 2022. It was a Republican… https://t.co/WXA73YRtEV

— Katie Daviscourt 📸 (@KatieDaviscourt) November 3, 2024

Alaska:

Alaska isn’t a state most people think about when talking about highly contested races, but their campaigns, supporting political committees and other groups have spent $40 million on the race between incumbent Democrat Alaska Rep. Mary Peltola and Republican Nick Begich. Polling gives Begich a 4-point lead over Peltola, and 538’s election simulator gives him a 60% chance of winning. (ROOKE: Republicans’ Latest Swing State Win Is The Last Thing Democrats Want Right Now)

Neither party holds a large majority in either chamber, giving each a chance at flipping control. Republicans have a clear shot at flipping key Senate races, however, and could not only hold their current House majority but expand it.