The US Midterms, Explained

Congress is the part of America's government that makes the laws, and it has two chambers.

The House of Representatives has 435 members. Each represents a district of roughly 760,000 people and serves for two years, so every seat is up this time.¹

The Senate has 100 members, two for each state, who serve for six years. Only about a third of them face voters at any one election. This year it's 35 seats: the regular third, plus special elections in Florida and Ohio for the seats Marco Rubio and JD Vance left when they joined the administration.²

Thirty-six states also elect their governors, and there are thousands of state and local races. This explainer is about Congress.

America's government has three parts. The president runs the government. Congress, the House and the Senate together, makes the laws. And the courts decide what the law means, and whether the president and Congress have followed the Constitution. None of the three is in charge of the others: each can check the others' power.

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Inside Congress, the House and the Senate are equal partners. Neither is above the other. A new law starts as a bill: a proposed law, written down and put to a vote. To become law, the same bill has to pass both the House and the Senate. Then it goes to the president, who can sign it into law, or veto it, which means refusing to sign. Congress can overturn a veto, but only if two-thirds of both chambers vote to.

So whichever party controls each chamber decides which bills get a vote at all. That's why the midterms matter so much to a president.

A majority in the House takes 218 seats. Republicans hold 218 and Democrats 214. One seat is held by an independent, and two are empty after their members resigned. So Democrats need to gain just three seats to take control.³

In the Senate, Republicans have 53 seats and Democrats 47. If the Senate splits 50–50, the vice-president, JD Vance, casts the deciding vote. So Democrats need 51 seats, a gain of four.²

History favours the Democrats in the House. In almost every midterm since the Second World War, the party that holds the White House has lost seats in the House. This time, that's the Republicans. The only exceptions were 1998 and 2002.⁴ Voters often use the midterms to check the party in power.

Forecasters model elections from polls and past results, and rate each race by how likely each party is to win it. A "toss-up" means it could go either way.

The Cook Political Report, one of the best known, rates seven Senate races as toss-ups: Alaska, Iowa, Kansas, Maine, Michigan, Ohio and Texas. Six of the seven are held by Republicans now.²⁵

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Democrats have seats of their own to defend too, in Georgia, Michigan, Minnesota and New Hampshire. And in North Carolina, where the Republican senator Thom Tillis is retiring, the race leans towards the Democrats. Cook expects Democrats to gain between two and six Senate seats, so a majority is in reach but not certain.²⁶

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For the House, most forecasts favour the Democrats. Cornell's model, for one, gives them about an eight-in-ten chance of a majority.⁷⁸

But a forecast is a probability, not a result. Polls have missed in both directions in recent elections, and a few points either way in the toss-ups would change the outcome.

Something unusual happened before this election. The lines of House districts are normally redrawn once every ten years, after the census. This time, several states redrew them after just five years.

Drawing district lines to help one party win more seats is called gerrymandering. You pack your opponents' voters into a few districts, or split them across many, so their votes count for less.

Texas, run by Republicans, redrew its map to win about five more seats, and the Supreme Court let it stand. California's voters answered with Proposition 50, which passed by 65 to 35 and brought in a map designed to give Democrats about five more seats.⁹¹⁰¹¹ North Carolina and Ohio redrew theirs for Republicans too, and a court gave Utah a new map with one more Democratic seat.⁹

Then, in April, the Supreme Court's ruling in Louisiana v. Callais meant states no longer had to keep some majority-Black districts, and Florida, Tennessee, Louisiana and Alabama redrew as well, all towards Republicans.¹²¹³ Courts blocked new maps in Missouri, drawn for Republicans, and Virginia, drawn for Democrats.⁹¹⁴ In all, nine states vote on new lines this year.

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Add the estimates together and the new maps could be worth about nine seats to Republicans, though estimates differ and some maps are still being fought over in court.¹⁵

Each chamber has powers of its own.

The House starts every law that raises or spends money. So a House majority can refuse to fund the government, which forces a shutdown. It can call officials to give evidence and demand documents. And it can impeach a president, which means formally charging him, by a simple majority.

The Senate approves the president's choices for judges, the cabinet and ambassadors. It ratifies treaties. And if the House impeaches, the Senate holds the trial, where removing a president takes two-thirds of senators.

So there are three likely outcomes.

If Republicans keep both chambers, Trump keeps a Congress that can pass his plans, though most laws still need 60 of the 100 Senate votes, because of the filibuster: a rule that lets a minority of senators block most bills.

If Democrats win the House only, they can block his legislation and investigate his administration. But they can't make their own plans law without the Senate and his signature.

If Democrats win both, they could pass their own bills and send them to him. But he can veto them, and overturning a veto takes two-thirds of both chambers, which neither party will have.

Both parties are making promises. We test them the same way we tested Trump's in Trump: Promises vs Reality: can they actually deliver them, and are the claims behind them true?

The Democratic leader in the House, Hakeem Jeffries, names three priorities: lower prices, affordable health care, and holding Trump's administration to account. Their most specific plans are on health care.¹⁶¹⁷¹⁸

First, restore the extra tax credits that helped people pay for insurance bought through the Affordable Care Act, the health law often called Obamacare. Those credits expired at the end of 2025, and several million people have dropped their cover since: KFF counts 4.6 million fewer people in the individual market between June 2025 and June 2026.¹⁷¹⁹

Second, reverse the cuts to Medicaid, the government's health insurance for people on low incomes, made by last year's big Republican tax and spending law. The Congressional Budget Office, Congress's own nonpartisan scorekeeper, estimated that law would leave about 10 million more people uninsured by 2034.¹⁷²⁰

They would also hold votes to end the war with Iran and to roll back Trump's tariffs.¹⁷

Can they deliver? Not with the House alone. Each would need the Senate, and then Trump's signature, or two-thirds of both chambers to overturn his veto. What a House majority can do is force votes, put the questions on the record, and use the fights over government funding as leverage. Some Democrats admit the limits. "We will not be able to fix everything overnight," says Representative Troy Carter.¹⁷

And are the claims behind it true? Mostly. The exception is Medicare, the health insurance for over-65s. Democratic adverts have said the Republican law cuts it, and FactCheck.org found they exaggerate: the law's main cuts fall on Medicaid.²¹

Republicans are running mostly on the record of the last two years, which we tested promise by promise in Trump: Promises vs Reality. But Trump has made new offers for this election.

The biggest is a payment of $5,000 to every adult citizen if Republicans keep Congress.²²²³

Can it be delivered? Trump has said he doesn't think it needs Congress's approval. But like any government spending, it would need a bill passed by Congress, as the Republican Speaker of the House, Mike Johnson, has said. There's no plan or timetable yet.²²²⁴ With about 245 million adult citizens, it would cost about $1.2 trillion; PolitiFact put it at more than $1 trillion.²³

Trump says tariffs and growth would pay for it. Tariffs brought in about $173 billion in the year to September, after the refunds the Supreme Court's ruling against his emergency tariffs forced, so the payment would cost around seven years of them.²⁵ And tariff money comes mostly from Americans themselves: the tax is paid at the border by American companies, and economists at the Federal Reserve Bank of New York found Americans bore nearly 90 per cent of the cost of last year's tariffs.²⁶ So if tariffs paid for it, and nothing else changed, Americans would largely be paying for their own cheques, through the higher prices tariffs bring.

Growth does bring in more tax, as a bigger economy pays more. But the Congressional Budget Office expects the economy to grow about 2 per cent this year, and no official forecast we found expects growth to raise anything like $1.2 trillion extra.²⁷

He has also said oil prices will be "tumbling downward" right after the election, though in the same breath he said it might take a little longer.²⁸²⁹ Oil and petrol prices depend mostly on the world market and the war with Iran, which no election result controls.

So: two parties, two kinds of promise. The Democrats are promising things a House majority can't deliver on its own. The Republicans are promising a payment with no plan behind it yet.

Voting ends on the evening of Tuesday 3 November. Results are usually given in Eastern Time, the time in Washington and New York. The first polls close at 6pm Eastern, in parts of Indiana and Kentucky, which is midnight in central Europe. The last, in Alaska's Aleutian Islands, close at 1am Eastern, early on Wednesday 4 November: 7am in central Europe.³⁰

Some results come in overnight. But many states count postal ballots after the polls close, and close races can go to recounts, so control of the House or the Senate may not be known for days.

Midterms usually decide whether a president spends the second half of his term passing laws or fighting Congress. This one is also a test of the redrawn maps, of what happened after Obamacare's extra help ended, of Trump's own promises, and of whether the support that won him the 2024 election has held after two years in office.

We'll look at the results when they're in.