Races to watch in Tuesday's midterm fight for Congress

Tuesday's midterm elections will decide whether Republicans keep Congress in their hands or Democrats gain enough leverage to slow President Donald Trump's agenda over his final two years in office, while also creating further headaches for President Trump.

Here is the arithmetic: House Democrats must pick up a net three seats to hit the 218-seat majority threshold. Republicans control the Senate 53–47, meaning Democrats need a net gain of four to reach 51, because a 50–50 split would keep Republicans in charge through Vice President JD Vance's tie-breaking vote.

Republican-held Senate seats Democrats are trying to flip

North Carolina and Maine sit at the center of the Democratic path. In North Carolina, Roy Cooper, the former Democratic governor, is running against Republican Michael Whatley for the seat occupied by retiring Republican Sen. Thom Tillis. Maine puts Republican Sen. Susan Collins up against Democrat Troy Jackson. In a state that Kamala Harris carried in 2024, Collins's ability to pull in crossover voters carries particular weight.

Decisive gains could come from Ohio and Texas. The Ohio special election pits former Democratic Sen. Sherrod Brown against Republican Sen. Jon Husted. In Texas, Republican Ken Paxton and Democrat James Talarico face off in a closely watched race after Paxton beat incumbent John Cornyn in the primary. The pair of contests tests whether Democrats can win statewide in Republican-leaning territory.

Other paths run through Alaska, Iowa and Kansas. In Alaska, Republican Dan Sullivan is opposed by Democrat Mary Peltola; in Iowa, Republican Ashley Hinson and Democrat Josh Turek compete for the open seat; and Kansas Republican Sen. Roger Marshall faces Democrat Adam Hamilton. Should Democrats come up short elsewhere, these races offer alternative routes.

The Democrats also have seats of their own to defend

Michigan is a crucial hold, with Democrat Abdul El-Sayed and Republican Mike Rogers competing for the seat of retiring Democratic Sen. Gary Peters. Georgia pairs Democratic Sen. Jon Ossoff against Republican Mike Collins. New Hampshire's open Democratic seat sees Chris Pappas take on Republican John E. Sununu.

Each lost Democratic seat raises the bar. If Democrats lost a seat they now occupy, reaching 51 would require flipping five Republican seats.

In the House, Pennsylvania could prove decisive

Three Republican-held Pennsylvania seats are drawing particularly close attention:

• 7th District: Democrat Bob Brooks takes on Ryan Mackenzie.

• 8th District: Democrat Paige Cognetti takes on Rob Bresnahan.

• 10th District: Democrat Janelle Stelson takes on Scott Perry.

Each of those three Republican incumbents won narrowly in 2024. Sweeping just these seats, with no other district changing hands, would be enough for Democrats to take the House.

Additional Republican-held battlegrounds are Michigan's 7th, Wisconsin's 3rd, Iowa's 1st and 3rd, New York's 17th, Virginia's 2nd and Arizona's 6th. With the majority so narrow, the speaker's gavel could be decided by individual district results.

Market implications

If Republicans control both chambers, Trump's clearest route for advancing legislation remains intact. A Democratic House would force more negotiation over spending and major policy changes. Democratic control of the Senate would also give the party more influence over appointments and confirmations.

For traders, the vote acts as a catalyst to reassess taxes, spending, regulation and borrowing. The scale of the majorities matters as much as which party comes out ahead: a slim majority could leave Washington struggling to turn campaign pledges into policy.