US mid-term elections 2026: 7 things that could decide who controls Congress

The election will take place on November 3. All 435 House seats and 35 of the 100 Senate seats are on the ballot.

Democrats appear better positioned to win the House, while the Senate race remains too close to call, reported Reuters. Republicans, however, have important structural advantages, including newly redrawn Congressional maps and a Senate map that forces Democrats to compete in several states that Trump won in 2024.

The outcome will depend on more than Trump’s approval rating. The price of food and fuel, the number of competitive House districts, redistricting, a small group of Senate battlegrounds, the Iran war, voter turnout and campaign spending could all shape the result.

Here are seven factors to watch.

1. Trump’s approval rating

Trump’s standing with voters is one of the biggest challenges for Republicans heading into November.

Trump’s approval rating had fallen to an all-time low in the latest Reuters/Ipsos polling. His net disapproval was nearly twice as high as it was at the same point in 2018, when Democrats gained 40 House seats.

The same Reuters report said registered voters preferred Democratic candidates over Republican candidates by five percentage points. Democrats also reported stronger enthusiasm about voting, while recent special and primary elections showed strong Democratic turnout.

The effect could matter because mid-term elections often punish the party that controls the White House. The president’s party has lost House seats in all but two mid-term elections since 1938.

Jessica Taylor, a Senate analyst at the Cook Political Report, said affordability had become the most important issue for voters.

“I think that there is just a general sense that the president is not focused on the number one issue with voters, which is affordability,” Taylor told Reuters.

A weak presidential approval rating does not automatically determine the result. Republicans still have advantages in several parts of the country, and Democrats face their own divisions between moderate and progressive voters.

But Trump’s standing could influence how voters treat Republican candidates who are closely associated with him.

2. The cost of living – especially prices 

Prices could become one of the most important issues of the 2026 election. A Reuters/Ipsos poll published on August 25 found that 36% of registered voters said Democrats had the better approach to the cost of living, compared with 28% who chose Republicans.

The eight-point Democratic advantage was the party’s biggest lead on the issue since Reuters/Ipsos began asking the question in October 2025.

The poll also found that 37% of voters either were unsure which party had the better approach or believed neither party had a good one.

The issue has become more politically important because the Iran war has pushed up energy costs. Gasoline prices had moved close to record highs after the conflict began, reported Reuters.

Republicans have tried to counter the Democratic message by pointing to Trump’s tax cuts and other policies. Republican strategist Jeanette Hoffman told Reuters in August that Democrats should not feel overly confident because a large share of voters remained unconvinced by either party.

The cost of living could therefore become a test of which party can persuade voters that it has a credible answer to high prices.

Texas offers one example. Democratic Senate candidate James Talarico has used grocery bags in television advertising to focus attention on higher prices.

The issue also appears in Republican campaign advertising. Trump’s political group, MAGA Inc., committed $10 million to television and digital advertising in the Texas Senate race, reported AP. The ads attacked Talarico over taxes and argued that Republican candidate Ken Paxton would offer tax breaks to some households.

3. The House map — Democrats only need 3 seats 

The House could provide Democrats with their clearest route back to power. Republicans currently hold 218 seats compared with 214 for Democrats, according to Reuters report. That means Democrats need a net gain of three seats to take control.

Only about 50 of the 435 House races are expected to be competitive, reported Reuters. Those contests could determine which party controls the chamber.

The battlegrounds include districts in Arizona, California, Colorado, Florida, Iowa, Michigan and New Jersey.

California could be especially important. Democrats redrew the state’s congressional map last year after Republican-led states changed their maps. Analysts said the California map could help Democrats gain five Republican-held seats.

Iowa has also become more competitive. Reuters reported that concerns over Trump’s tariffs and higher fuel and fertiliser costs linked to the Iran war have put several races in play.

The House race is therefore not simply a national vote. A small number of districts could determine whether Democrats take the chamber.

A Democratic House majority would also have consequences for Trump’s presidency. Democrats could launch investigations into his administration and force the White House to negotiate more often on legislation, reported Reuters.

4. Redistricting could blunt a Democratic wave 

The House map gives Republicans an important advantage even as Democrats seek to gain seats.

Several Republican-led states redrew congressional districts before the midterms after Trump pushed for changes. Democrats responded in California with their own redistricting effort.

The redistricting fight had spread across several states and represented an unusual mid-decade effort to reshape congressional districts before an election, according to Reuters report.

A May 3 Reuters analysis found that the number of competitive House districts had already fallen close to historic lows before the Supreme Court opened the door to more aggressive partisan redistricting.

The lack of competitive races meant that fewer than 10% of Americans could effectively determine control of the House in November because many district outcomes were already heavily tilted toward one party, reported Reuters.

The new maps could therefore limit how many seats Democrats can gain even if they perform strongly in the national vote.

Republicans could gain as many as 10 additional House seats based solely on the redrawn maps, reported Reuters.

That gives the Republican Party a structural defence against a possible Democratic wave.

5. The nine Senate battlegrounds 

The Senate presents a much harder path for Democrats. Republicans hold a 53-47 majority, and Democrats need to gain four seats to control the chamber. Independent analysts consider only nine of the 35 Senate races on the ballot to be competitive, reported Reuters.

North Carolina is one of the main Democratic opportunities. Republican Senator Thom Tillis is retiring, while former Democratic Governor Roy Cooper faces Republican Michael Whatley.

Michigan is another key contest, but Democrats must defend the seat held by retiring Senator Gary Peters. Democratic nominee Abdul El-Sayed faces Republican Mike Rogers in a race that Reuters said analysts rate as a toss-up.

Texas has also entered the battleground list. Democratic state Representative James Talarico faces Republican Attorney General Ken Paxton. Reuters said analysts view the contest as a toss-up despite Texas’ Republican lean.

Other closely watched races include Alaska, Iowa, Maine and Georgia.

In Alaska, Republican Senator Dan Sullivan faces Democrat Mary Peltola. Reuters reported that Peltola won more votes than Sullivan in the state’s August nonpartisan primary, although analysts still rate the general election as a toss-up.

In Iowa, Republican Representative Ashley Hinson is running for the seat of retiring Senator Joni Ernst against Democratic state Representative Josh Turek. 

Maine presents another difficult contest for Republicans. Democratic candidate Troy Jackson faces Republican Senator Susan Collins, a moderate who has won reelection several times even as Maine backed Democratic presidential candidates.

Georgia has Democratic Senator Jon Ossoff running against Republican Representative Mike Collins, who has Trump’s backing.

Even if Democrats win difficult races in Georgia, Maine, Michigan and North Carolina, they would still need to take at least two of four states that Trump won by double digits in 2024: Alaska, Iowa, Ohio and Texas, as reported by Reuters.

That makes the Senate math significantly more difficult than the House math.

6. Iran war and foreign policy 

Foreign policy could also affect the mid-terms, particularly if the Iran war remains a major concern for voters in the final weeks. A Reuters/Ipsos poll published on September 4 found that only about one-quarter of Americans believed the war with Iran had been worthwhile.

Trump’s advisers wanted to prevent the unpopular conflict from escalating and dominating the political debate before the mid-terms.

The war also has an economic impact. Higher energy prices have fed directly into the cost-of-living debate, giving Democratic candidates another issue with which to challenge Republicans.

The political effect is not limited to national polling. Iowa farmers faced higher energy costs and the impact of Trump’s tariffs. Texas cattle ranchers had also expressed anger over Trump’s decision to lift import taxes on foreign beef.

Michigan and Maine could face effects from Trump’s escalating trade conflict with Canada, Reuters reported.

Trump has said the elections were not influencing his Iran strategy. But the conflict remains part of the political environment in which Republican candidates are trying to defend their seats.

7. Turnout, enthusiasm and campaign money 

Even if the political environment favours Democrats, turnout and campaign spending could determine whether that advantage becomes actual seats. 

Democrats had shown stronger enthusiasm about voting and had recorded robust turnout in recent special and primary elections. But Republicans have a major financial advantage at the national level.

Democratic candidates had outraised their Republican opponents in many individual House contests. Republican national party committees and Republican-aligned super PACs, however, had spent far more than their Democratic counterparts.

Trump’s own political organisation, MAGA Inc., had a war chest of about $400 million, according to Reuters report.

MAGA Inc. had begun deploying that money in the Texas Senate race, committing $10 million to television and digital advertising, reported AP.

Earlier in the year, Reuters had also found a Democratic fundraising advantage among candidates in key competitive House districts. In a February 23 analysis, Reuters found that Democratic candidates challenging Republican incumbents had raised about $50 million, compared with roughly $20 million raised by Republican candidates challenging Democratic incumbents across the districts examined.

The financial picture was different for incumbents. Incumbents in competitive districts, regardless of party, had raised more than $84 million in the previous year, reported Reuters.

Money alone will not determine the election. But it can give candidates more resources for advertising, voter outreach and campaign organisation during the final weeks.

The final outcome will depend on how these factors interact.

Disclaimer: This article examines the key factors and competitive races that could influence control of the US House and Senate in the November 3, 2026 midterm elections. It does not predict the election outcome. Race ratings, polling figures and campaign developments can change before Election Day.