Democrats win US Congress: How they did it and what it means

The Democratic Party has scored a stunning victory in the United States midterm elections, flipping a string of bellwether seats to secure comfortable control of both the Senate and the House of Representatives. The party has won 53 seats in the 100-seat Senate and leads in three more, while The Associated Press reported it had also taken the House, crossing the 218-seat mark needed for a majority in the 435-member chamber.

The result marks the first time since Barack Obama's second term that an incumbent president has been left without either chamber of Congress on his side. With several races still too close to call, final results could take days, but many Democrats have already framed the outcome as a defeat for President Donald Trump, who has himself conceded that his opponents outperformed his party's campaign.

The Senate gains included territory Democrats had not won in generations. In Texas, James Talarico defeated Ken Paxton, the state attorney general endorsed by Trump, by more than 11 percentage points, becoming the first Democrat to win a statewide race in Texas in 32 years. In Kansas, Adam Hamilton beat Trump-backed Republican Roger Marshall in a state where Democrats last won a Senate seat in 1932.

Other flips came across the map. Josh Turek won Iowa's competitive Senate race by 4 percentage points, and in South Carolina, Annie Andrews claimed the seat long held by Trump ally Lindsey Graham until his death earlier this year, defeating his sister Darlene, who had been appointed to fill the seat and was strongly backed by Trump. Roy Cooper delivered a blowout in North Carolina, beating Republican Mike Whatley by almost 20 points, while Troy Jackson unseated Susan Collins in Maine by nearly 7 points and Sherrod Brown won Ohio by almost 4. In Michigan, Abdul El-Sayed leads Republican Mike Rogers and has claimed victory; a win would make him the first Muslim senator in US history.

Democrats campaigned on ending the war on Iran, bringing down the cost of living and holding the Trump administration accountable for alleged abuses of power. Delivering on those promises may prove difficult, though the Senate majority brings significant leverage: the chamber alone can approve presidential nominations, meaning Democrats can block Trump's picks for ambassador posts, cabinet positions and federal judgeships, including the Supreme Court. The majority also controls committees that can open investigations, demand documents and compel testimony.

Legislating will be harder. Trump has signalled he will use his veto freely, telling a podcast on Monday, "I'll veto everything." Overriding a veto requires a two-thirds majority in both chambers, so Democrats would need Republican votes even for measures with bipartisan support, such as raising the minimum wage.

On accountability, Laura Blessing, a senior fellow at Georgetown University's Government Affairs Institute, expects a Democrat-led Congress to use its investigative powers aggressively. Senator Richard Blumenthal, the ranking Democrat on the Senate's Permanent Subcommittee on Investigations, is expected to become its chair and told Reuters before the vote, "We will use our subpoena power, absolutely." Such inquiries, which need no White House approval, could probe a Trump family business empire that has expanded into cryptocurrency, drones, artificial intelligence and prediction markets, while Trump's personal wealth has grown by an estimated $2.2bn, according to financial disclosure forms released this year. Officials could still challenge subpoenas in court, delaying inquiries for months or years, and any evidence of possible crimes would ultimately land with Trump's own Justice Department. Senator Sheldon Whitehouse urged a strategic balance, telling The Hill that investigations should not distract "from solving fairly immediate cost problems that American families feel."

On the war with Iran, timing looms large. The Democratic majority does not take control of the Senate until January 3, and Trita Parsi, executive vice president of the Quincy Institute for Responsible Statecraft, warned Trump could escalate before then, saying that "in the face of humiliation and defeat, he becomes more reckless." Once in power, Democrats could try to choke off further war funding, though any budget bill could face a veto and Democrats have historically hesitated to withhold military money for fear of being accused of undermining US troops. David Janovsky of the Project on Government Oversight said rigorous oversight alone "could raise the political costs of the war beyond what the president or other key officials are willing to endure." Parsi cautioned that failing to act would leave Democrats sharing ownership of the conflict.

On the cost of living, voters' top concern heading into the election, economist Dean Baker of the Center for Economic and Policy Research argued that ending the war could bring down petrol prices, since Iran has restricted commercial traffic through the Strait of Hormuz, a vital fuel and fertiliser route, since the conflict began in February. Democrats could also use spending negotiations to restore expired enhanced Affordable Care Act subsidies and reverse cuts to Medicaid, while committee gavels would let them summon executives over grocery prices, rents and electricity bills. Alex Jacquez of the Groundwork Collaborative cautioned that relief would be gradual: "Prices are like rockets and feathers. They shoot up like rockets; they come down like feathers."