With Congress in the hands of Democrats, the calculus of American politics is changing

The Democratic Party pulled off a major upset in the US midterm elections, winning several key seats and securing majorities in both houses of Congress.

The AP news agency reported that the party won the Senate and House of Representatives, marking the first time since Barack Obama's second term that a sitting president has failed to retain a majority in either chamber of Congress.

Some Democratic leaders have already portrayed the results as a defeat for President Donald Trump, who himself has acknowledged that his party has been outmaneuvered by his opponents in the election campaign.

This report looks at how Democrats gained control of Congress and what they can do with this power.

A large majority in the Senate

Democrats have won several seats in the Senate, including many that the party has not won in decades.

James Talarico, Texas: Trump won the state by 14 percentage points in the 2024 presidential election. He endorsed state Attorney General Ken Paxton. Paxton has been indicted on fraud charges and has been impeached by the state legislature once. However, with most votes counted, Talarico beat Paxton by more than 11 percentage points. He is the first Democrat to win a statewide election in Texas in 32 years.

Adam Hamilton, Kansas: Hamilton had a bigger success in Kansas than Tallarico did in Texas since 1994. He defeated Republican candidate Roger Marshall, who is endorsed by Trump. Democrats last won a Senate seat in Kansas in 1932.

Josh Turek, Iowa: Trump won Iowa by 14 percentage points in 2014. However, Turek won this year's competitive Senate race by four percentage points.

Annie Andrews, South Carolina: Trump won this state by a wide margin in the 2024 election. It was the seat of longtime Senator Lindsey Graham, a Trump ally who died earlier this year. Graham's sister Darlene had been given the seat until the election. Trump also strongly endorsed her. But Andrews ultimately won by at least four percentage points.

Roy Cooper, North Carolina: Cooper won a landslide victory in a seat previously held by the Republicans, defeating Republican candidate Mike Watley by nearly 20 percentage points.

Troy Jackson, Maine: Jackson captured the Republican-held seat, defeating Susan Collins by nearly seven percentage points.

Sherd Brown, Ohio: Brown defeated Republican candidate Jon Husted by about four percentage points.

Abdul El-Sayed, Michigan: El-Sayed defeated Trump-backed Republican Mike Rogers to become the first Muslim U.S. senator.

Victory in the House of Representatives

According to AP data, Democrats have secured victory, surpassing the 218 seats needed to gain a majority in the 435-member House of Representatives. The victory includes several seats previously held by Trump's Republican Party.

Hours after the Senate victory was announced, the AP reported the Democrats' victory in the House of Representatives, giving the party control of both chambers of Congress.

Democrats have promised to end the war with Iran, lower the cost of living, and hold the Trump administration accountable for abuses of power if they win the election. But fulfilling these promises will not be easy.

How much power does the Democrat-controlled Congress have?

The House of Representatives and the Senate play important roles in making laws and approving government spending. However, neither chamber can make all decisions alone. Furthermore, both chambers have some powers that the other does not have.

For example, the Senate has sole authority to approve the president's top government nominees. With a majority in the Senate, Democrats can block Trump's nominees for ambassadors, cabinet members, and federal judges. This would even include Supreme Court justices.

The majority party in the Senate also controls various committees. These committees can launch investigations, subpoena documents, and order witnesses to appear for questioning.

In addition, if a president or top government official is impeached by the House of Representatives, the Senate is responsible for conducting the trial. The trial may also result in a decision to remove the accused person from office.

Trump was impeached twice during his first term, in 2019 and 2021. However, he was acquitted in the Senate both times.

A majority in the Senate would also give Democrats more power to make laws. To become law, a bill must pass both houses of Congress. It then needs to be signed by the president.

But Trump's veto power could be a major obstacle to Democrats' legislative plans. Even bipartisan proposals like raising the minimum wage could face the president's veto. "I'll veto everything," Trump said in a podcast on Monday, signaling a broad use of his veto power.

To override a presidential veto, a two-thirds majority in both the House of Representatives and the Senate would be required, meaning Democrats would need the support of some Republicans.

Can Congress hold Trump accountable?

Laura Blessing, a senior fellow at Georgetown University's Government Affairs Institute, believes that the Democrat-controlled Congress will actively use the constitutional power of investigation.

"The Democrats will be the most active in terms of time spent and newspaper headlines on the investigation," he told Al Jazeera in an email.

Richard Blumenthal, the current senior Democrat on the Senate Permanent Subcommittee on Investigations, is likely to become chairman of the committee due to Tuesday's election results.

Blumenthal told Reuters in September, ahead of the midterm elections, that they would use their congressional majority power to investigate the Trump administration. "We will certainly use the subpoena power," he said.

Congress can conduct investigations without White House approval, which could create an uncomfortable situation for Trump. In the past two years, the Trump family has expanded its business into a variety of sectors, including cryptocurrency, drones, artificial intelligence and prediction markets.

According to financial statements released this year, Trump's personal wealth has increased by an estimated $2.2 billion.

Democratic senators have already begun preparing for such an investigation. Some senators have sent letters to various companies and government agencies demanding the preservation of relevant documents.

The letters raise a variety of issues, including Trump's collection of private donations to build a White House ballroom and allegations of politically motivated investigations.

But there are questions about whether everyone will cooperate with the investigation. Trump administration officials could challenge the Senate subpoena in court in the future, which could delay the investigation for months or even years.

Blessing believes it is unlikely that Trump's immediate family members will be subpoenaed, but Democrats will be able to question government employees and people working at various institutions associated with Trump's inner circle.

This could reveal information about possible irregularities against Trump and his allies. However, there is no guarantee that legal action will be taken if such information is found. Democrats can send evidence of possible crimes to prosecutors. But the decision whether to file charges or not will be up to Trump's Justice Department.

Impeachment proceedings may also be initiated if information about a crime is found. However, no US president has been removed from office through such a process so far.

This has raised questions among some Democratic leaders about how much time should be spent investigating Trump, and how much time should be devoted to issues that directly affect voters.

"We need to be thoughtful and strategic about where the investigation is going, while also making sure we don't lose focus on solving the urgent spending crisis that is impacting the daily lives of American families," Democratic Senator Sheldon Whitehouse told The Hill on Tuesday.

Can the Democratic Congress stop a war with Iran?

Democrats' majority control of the Senate will not take effect until January 3. As a result, the next two months could be crucial for the Iran war, says Trita Parsi, executive vice president of the Quincy Institute for Responsible Statecraft, a foreign policy research organization.

He fears that Trump could intensify the war against Iran before Democrats take control of the Senate in response to the midterm election defeat.

"We have seen a tendency for him to become more reckless in the face of humiliation and defeat," Parsi said.

Parsi believes that once Democrats take control of the Senate, they will have to take tougher steps to limit Trump's war-making powers. In this case, they could take steps to limit funding for the war.

The Trump administration will be able to continue spending previously allocated funds for military operations, but Democrats could block new funding for the war because of control of Congress.

"This will put a limit on how long he can continue the war," Parsi said. "If he needs new money to continue the war, it's not a small amount that can be easily diverted from other sources."

But any budget bill would need enough votes to overcome Trump's potential veto to pass, and there are also questions about how willing Democrats are to limit military spending.

Blessing said Democrats have historically been reluctant to cut military funding for fear of being accused of weakening the US military.

But there are other ways for them to increase pressure to end the war. For example, the party could use Senate control to investigate whether the Trump administration followed the rule of law in conducting the war and the attacks.

"Tougher surveillance alone won't limit military operations," said David Janowski, a policy analyst at the Project on Government Oversight, an independent watchdog group. "But it can increase the political costs of war to a level that the president or key officials may not want to bear."

It is not yet clear whether Democrats will unite to end the war, but Percy warns that the party could suffer political consequences if it does not try to contain Trump.

He said, "Then it will no longer be just Trump's war. They will also become partners in it. Because, despite having the power to stop the war, if they do nothing, the responsibility will fall on them as well."

Can the Democratic Senate reduce the cost of living?

The economic crisis was one of the top concerns for voters ahead of the midterm elections.

Economist Dean Baker, co-founder of the Center for Economic and Policy Research, believes that one of the biggest steps Democrats can take to alleviate these concerns could be to take steps to prevent a war with Iran.

Since the war began in February, Iran has restricted commercial shipping through the Strait of Hormuz, a vital waterway for global energy and fertilizer trade.

According to Baker, the opening of a Senate investigation into the Trump administration's role in waging the war could increase political pressure to end the war. This could lower oil prices and ease some of the pressure on household spending.

Democrats may also take initiatives to reduce healthcare costs.

Many Americans are paying higher premiums for health insurance as the Affordable Care Act's expanded subsidies expire in 2025. Democrats could seek to reinstate those subsidies, as well as roll back cuts to Medicaid, the government health care program for low-income people.

Baker said Democrats could pressure Republicans to agree to these measures during the government spending talks. Given the bipartisan support and broad public support, it could be politically difficult for Trump to veto the health care spending cuts.

Referring to the Democrats, he said, "They can create a political situation so that Trump does not want to veto the bill."

Democrats could also try to roll back the tariffs imposed by Trump, but that would require the support of the House of Representatives and enough votes to approve Trump or override his veto.

Even if such initiatives are successful, commodity prices will not fall overnight. "Prices go up like rockets, but they come down like feathers," said Alex Jacquez, head of policy and advocacy at the progressive economic research organization Groundwork Collaborative.

But Democrats have another way to combat high prices, beyond Trump's approval. They can use their control of Senate committees to investigate companies on everything from groceries and rent to high electricity bills.

"There are many examples of the committee having the leadership power and subpoenaing company CEOs to appear before Congress to bring about real change," Jacquez told Al Jazeera.