From Michigan to Texas, from Pennsylvania to Alaska, the majority in Congress hinges on a handful of contests. In some cases, the selection of highly ideologically polarised candidates has turned predictable elections into open contests, and the results will also reveal which strategy works best against the opposition: winning over the centre or mobilising one’s own base?

The US mid-term elections will be held on 3 November across the United States, but the battle for control of Congress will be fought in a surprisingly small part of the country.

All 435 seats in the House of Representatives will be up for election. In the Senate, only 35 out of 100 seats are up for election. But to understand who will control Washington during the final two years of Donald Trump’s term, one need only focus on around twenty House constituencies and eight states for the Senate.

This is a consequence of the growing geographical polarisation in the United States. Most constituencies will, unsurprisingly, elect either a Democrat or a Republican. The majority, however, is decided in an increasingly narrow band of suburban, industrial or politically divided areas, stretching from Pennsylvania to Arizona and from Michigan to Virginia.

This year, however, there is an additional factor: the primaries have altered the dynamics of some of these races and, in some cases, have helped to broaden the competitive landscape.

The reason is simple: the electorate that decides a primary is not the same as the one that decides a general election. To secure the nomination, one often has to convince the most committed and ideologically driven voters within one’s own party. In November, in a closely contested constituency, however, one must win over independents, moderates and, at times, people who voted for the other party’s presidential candidate two years earlier.

This is where the 2026 mid-term elections become more than just a referendum on Trump. They are also a test of the internal transformations taking place within the two major American parties.

Four seats to cripple the duck

The toughest battle is the Democrats’ fight for the Senate. The Republicans currently hold 53 seats, compared with 47 for the Democratic bloc, which also includes independents. A net gain of four seats is therefore needed to change the majority.

At the start of the cycle, the road seemed very narrow. It still is today, but the map has expanded.

The eight races to watch are Michigan, Georgia, North Carolina, Maine, Alaska, Ohio, Texas and Iowa.

The first two are primarily democratic defences. The others represent, with varying degrees of difficulty, opportunities for conquest.

And it is precisely here that the primaries have produced some of the most interesting political experiments of the year.

Michigan: the left’s gamble

The most obvious example is Michigan.

Abdul El-Sayed narrowly defeated MP Haley Stevens. El-Sayed, a doctor and former head of public health in Detroit, belongs to the party’s progressive wing: he supports Medicare for All and greater economic redistribution. Stevens, on the other hand, represented the moderate Democratic model that enjoyed particular success in the suburbs during the Trump years.

The contest was therefore also between two electoral theories.

The first argues that, to win the swing states, the Democrats must win over independents and moderates. The second believes that a more distinctly progressive platform could mobilise young people, minority groups and a section of the electorate that does not normally vote.

El-Sayed will face the Republican Mike Rogers, who is backed by Trump.

Michigan thus becomes a national testing ground. If El-Sayed retains a Democratic seat in a closely contested state, the party’s left wing will be able to argue that the electability of progressives has been underestimated. If he loses, the moderates will almost certainly use the result to support the opposite argument.

Texas: the opposite risk for the Republicans

In Texas, the problem lies on the other side.

Under normal circumstances, the race for a Senate seat in a state that Trump won by a clear margin in 2024 would not be a national priority for the Democrats. Yet Texas has become a battleground.

The Republican Ken Paxton is one of the most recognisable figures on the Trump-aligned right. He has built his career on his alliance with Trump and on taking very clear-cut stances in the cultural and institutional battles that have transformed the Republican Party. Paxton’s victory presents the Democrats with a far more polarising opponent.

The Democrats are fielding James Talarico against him – a young state representative, former state school teacher and seminarian (he is studying at a Presbyterian seminary to become an ordained minister) – who is running a campaign designed to appeal to independents and moderate Republicans as well.

The race is now essentially neck and neck in the polls, and the Cook Political Report has reclassified it from a Republican lead to a ‘Toss-up’ (undecided).

It is difficult to prove that a more moderate Republican would automatically have maintained the party’s structural advantage, but the political reality remains: a race that, on paper, should have been relatively straightforward for the GOP has turned into one of the key national contests.

One of the risks of primaries is precisely this: a candidate who is perfectly suited to the party’s most loyal supporters may, in fact, prove less effective when the electorate as a whole is taken into account.

Alaska: the Peltola model

Alaska tells a completely different story.

Mary Peltola is probably one of the most successful examples of a strategy that runs counter to El-Sayed’s. A centrist Democrat and the first Alaska Native to be elected to Congress, she has forged a strongly local political identity, focusing on fisheries, energy, natural resources and the cost of living, whilst maintaining a certain distance from the national Democratic Party.

In the top-four primary on 18 August, he finished ahead of the outgoing Republican Senator Dan Sullivan.

The system in Alaska means the result differs from that of a traditional primary: Democrats and Republicans take part in the same ballot, and the top four candidates go through. But the fact that Peltola is ahead of an incumbent Republican senator in a state that consistently votes for the right in presidential elections is significant nonetheless.

His strategy is clear: to convince a section of the electorate that they can vote for Trump for the White House but for a Democrat in the Senate, provided that candidate appears sufficiently independent of her party.

It’s almost the reverse of the Michigan experiment.

North Carolina: the moderate approach

The same principle, in a more traditional form, underpins Roy Cooper’s candidacy in North Carolina.

Cooper served two terms as a Democratic governor in a state that, at the same time, voted Republican in the presidential elections. He is a moderate, understands the suburban electorate and has already demonstrated his ability to win votes beyond the Democratic base.

He is up against Michael Whatley, former chairman of the Republican National Committee and a candidate backed by Trump.

For the Democrats, North Carolina is probably their most likely chance of victory. If they fail to win there, securing the four seats needed to gain control of the Senate would become much more difficult.

Maine: the Collins paradox

Maine, on the other hand, presents one of the most ideologically unusual contests.

The Democrat Troy Jackson has a background in the world of work and trade unions. A former logger, he focuses his political agenda on wages, employment, healthcare and rural communities: a trade union-backed progressive with a working-class orientation.

On the other hand, there is Susan Collins, one of the last true moderates in the US Republican Party.

Collins has come through almost the entire Trump era whilst maintaining an unusual position within the GOP: conservative on many issues, but willing to break ranks with the party and the president on certain key matters.

The race in Maine is therefore the opposite of the pattern seen in Texas: not progressives versus MAGA, but the trade union left versus moderate Republicans.

Iowa and Ohio: the battle for the working class

Iowa and Ohio, on the other hand, will test the Democrats’ ability to win back some of the electorate that has shifted towards Trump over the last decade.

In Iowa, Josh Turek presents himself as a pragmatic, working-class Democrat and emphasises his ability to work with Republicans. He is up against Ashley Hinson, a conservative with close ties to Trump.

The very fact that Iowa has become a toss-up is significant. Trump has won the state three times, and the Democrats have not won a major election there for years.

In Ohio, this strategy is even more evident. Sherrod Brown, born in 1952, is attempting to return to the Senate by relying on the approach that has characterised his entire career: trade unions, industry, wages, trade protectionism and the defence of the working class. Brown belongs to the labour tradition of the Democratic Party – an economic left that seeks to compete directly with Trump for the working-class vote. He will be challenging Jon Husted, the Republican senator appointed following JD Vance’s election as Vice-President.

The same battle is being fought in the House of Commons, constituency by constituency

Whilst the Senate comprises eight large committees, the same pattern is repeated on a smaller scale in the House of Commons.

There are currently 21 constituencies that are truly decisive, a small fraction of the total of 435.

The factor that works most in the Democrats’ favour is that many of these seats are currently held by the Republicans, so they can play the offensive rather than the defensive more often.

But here too, the candidates – with their profiles and their stories – are of the utmost importance.

Pennsylvania: the anti-MAGA laboratory

PA-10 (the constituency codes for the Chamber of Deputies are similar to our ‘Turin 1’ or ‘Sicily 2’) is perhaps the constituency that best sums up the contest.

Janelle Stelson is a moderate Democrat and a former television personality who is well known in the area. Scott Perry, on the other hand, was chair ofthe House Freedom Caucus and is one of the most recognisable figures of the MAGA right in the House of Representatives.

The two had already faced each other in 2024, when Perry won by about one point.

Stelson is explicitly seeking votes from independents and moderate Republicans, arguing that Perry is too ideological for that constituency. It is the sort of constituency where the difference between a traditional Republican and a candidate strongly associated with MAGA can prove decisive.

The question is not whether Perry is too far to the right for Republican voters. Clearly he is not, as he won the primary. The question is whether he is too far to the right for the average voter in the PA-10 constituency. This is a crucial distinction.

Arizona: the strategy to break down stereotypes

In AZ-01, the Democrat Amish Shah is standing against the Republican Jay Feely.

Shah, an A&E doctor and former state MP, is a moderate who is running a campaign that deliberately seeks to distance itself from the Democratic Party’s national image. He has secured the backing of major local law enforcement organisations and, as a state representative, has repeatedly voted with the Republicans on measures relating to public safety.

The strategy is similar to Peltola’s in Alaska: not to convince the moderate voter that the national Democratic Party is right about everything, but to convince them that that particular Democratic candidate can represent them.

It is a distinction that could prove decisive in numerous constituencies in the House of Commons.

Washington: the working-class Democrat

WA-03 is even more interesting.

In recent years, Marie Gluesenkamp Perez has become one of the most closely studied figures amongst Democrats seeking to regain competitiveness in rural and semi-rural America.

As the owner of a small business, she talks about manual labour, the right to repair, the cost of living and the divide between large, progressive cities and rural communities. On certain cultural issues, she holds considerably more moderate views than the national party.

His opponent, John Braun, is backed by Trump.

Here too, the divide is not simply between left and right. It is between a Democrat who is building a working-class and local identity and a Republican who is trying to nationalise the electoral contest around the Trump agenda.

Virginia: two veterans and the political centre

VA-02 offers yet another configuration.

Elaine Luria, a moderate Democrat and former Navy officer, is attempting to unseat Jen Kiggans, a Republican and fellow Navy veteran.

Kiggans has received Trump’s endorsement, but she does not belong to the same political camp as Scott Perry or Ken Paxton. She is a more institutional conservative, well-suited to a competitive constituency.

It is important because it serves as a reminder that Trump’s endorsement alone is not enough to define a MAGA candidate.

The Republican Party of 2026 still harbours significant differences: Susan Collins is not Jen Kiggans; Kiggans is not Scott Perry; Perry is not Ken Paxton. Treating them as a single bloc would prevent us from understanding precisely what these elections are gauging.

The issue is not whether one is moderate or radical

The same applies to the Democrats.

Peltola, Cooper and Stelson are seeking to appeal to the centre. El-Sayed is seeking to mobilise progressive support. Jackson and Brown are focusing on an economic policy closely linked to labour and trade unions. Gluesenkamp Perez is attempting to rebuild a working-class democratic identity that is culturally less progressive.

There is therefore no single democratic strategy for defeating Trumpism. Nor is there a simple rule stating that the more moderate candidate always wins.

A strongly progressive candidate can boost turnout amongst their core supporters. A moderate can win over independent voters but leave younger voters unimpressed. A MAGA candidate can mobilise people whom a traditional Republican would not bring to the polls.

The real issue is another: how far removed can a candidate be from the average voter in the constituency in which they are standing?

This is where a primary can decide a general election.

When a primary school expands its catchment area

Texas is the most obvious example. But the impact of the candidacies goes beyond the likelihood of any individual candidate winning.

If a seat that was supposed to be safe becomes a contest, the party is forced to spend money to defend it. And that changes the whole campaign.

A Republican Party forced to invest in Texas, Iowa or Alaska has fewer resources available to mount a campaign in Michigan or Georgia and to defend North Carolina, Maine and Ohio.

The same logic applies in the House of Representatives. If Scott Perry has to spend millions just to stay afloat in Pennsylvania, those resources cannot be used elsewhere.

This is why primaries can reshape the political landscape even when the candidate who wins them goes on to secure the seat.

It’s not just about who wins: it’s about how much it costs to do so.

Two parties under scrutiny

Politically, with the November elections, two more far-reaching changes will also be put to the test.

The first concerns the Republican Party.

Trump continues to wield enormous influence over the primaries. But the mid-term elections will reveal to what extent his support can be transferred to the candidates he backs, particularly in closely contested constituencies.

Winning a Republican primary thanks to MAGA voters and winning over a suburban independent in November are two very different propositions.

The second concerns the Democrats.

What is the most effective way to defeat Trumpism?

The approach taken by Peltola, Cooper, Stelson, Turek and Gluesenkamp Perez is to win over the local community, address local issues and forge a political identity that is, at least in part, independent of the national party.

El-Sayed’s approach is different: he offers a more distinctly progressive agenda and is able to mobilise voters whom democratic centrism can no longer inspire.

Brown and Jackson suggest a third way: a return to an economic left centred on jobs, wages, industry and trade unions.

Three different strategies for the same objective.

America with its few constituencies

This is the ultimate paradox of the mid-term elections.

Voting will take place across the United States, but the majority could be decided by a tiny area of land.

In the Senate, particular attention will need to be paid to Michigan, Georgia, North Carolina, Maine, Alaska, Ohio, Texas and Iowa.

In the House of Representatives, all eyes will be on a handful of constituencies, from Arizona to Pennsylvania, and from Virginia to Washington State.

For those who fancy a bit of fun with the midterm ‘Risiko’, the constituencies to keep an eye on in the House of Representatives are: AZ-01, AZ-06, CO-08, IA-01, IA-03, MI-07, NJ-07, NY-17, OH-07, OH-09, PA-07, PA-08, PA-10, TX-34, VA-02, WA-03, WI-03, CA-22, FL-25, NE-02 and NC-01.

Three matches will be played simultaneously at those few venues.

The first will determine who controls Congress during the final two years of Trump’s presidency.

The second will determine whether the Republican Party can continue to shift towards MAGA without paying a price in the key swing states.

The third could be even more important for the Democrats’ future: determining whether Peltola and Cooper’s centrist model, Brown and Gluesenkamp Perez’s working-class model, or El-Sayed’s progressive approach works best against Trump.

The 2026 mid-term elections will therefore inevitably be a referendum on the president.

But in the few states and constituencies that will decide the outcome, the election will also be something else: a referendum on what sort of candidate can still convince the ‘middle ground’ in America.