President Donald Trump will face a dramatically different political landscape when the new Democratic-controlled Congress takes office in January 2027, but he retains significant constitutional powers that limit what lawmakers can do to override his agenda.

The Democrats’ sweeping victory in Tuesday’s midterm elections means they will control both the House of Representatives and the Senate for the first time since 2023. This gives them powerful tools to check the president, but Trump’s veto pen and executive authority ensure he remains a formidable political force.

The power of the presidential veto

Trump’s most potent weapon against a Democratic Congress is his veto power. Under the US Constitution, the president can block any legislation passed by Congress. Overriding a presidential veto requires a two-thirds majority in both the House and Senate, an extraordinarily high bar that neither party is close to reaching.

With Democrats holding 228 House seats and 54 Senate seats, they fall well short of the 290 House votes and 67 Senate votes needed to override a veto. This means any legislation Trump opposes will likely die, even if it passes both chambers.

Trump acknowledged this reality before the election, telling reporters he expected to become “Mr Veto” if Democrats won control. He said he hoped to work out deals with the opposition, adding: “You have strong veto and you end up working out deals.”

The House already tested this dynamic in January when Republicans stuck with Trump and refused to override two of his vetoes.

What Congress can do

Despite the veto obstacle, a Democratic Congress gains several powerful tools to check presidential power.

The most immediate is control over federal spending. House Democrats will write the government’s budget bills starting in January 2027, giving them the “power of the purse” to fund or defund Trump’s priorities. However, Trump can veto any spending bill he dislikes, potentially triggering government shutdowns.

Democrats also gain subpoena power, allowing them to issue legally binding requests for documents and testimony. House Democratic leader Hakeem Jeffries has outlined plans for aggressive oversight of the Trump administration, focusing on healthcare, immigration enforcement, and the president’s business dealings.

Representative Robert Garcia, expected to chair the House Oversight Committee, has vowed to investigate Trump family corruption, including the president’s cryptocurrency ventures worth more than $1 billion. He warned Republicans on social media to “lawyer up”.

Representative Jamie Raskin, likely to chair the House Judiciary Committee, plans to probe the Justice Department’s attempted prosecutions of political opponents and allegations of “pay-to-play” pardons.

Senate control blocks appointments

Control of the Senate gives Democrats the authority to confirm or reject Trump’s nominees for federal judgeships and Cabinet positions. This could prove particularly significant if a Supreme Court vacancy emerges during the next two years.

The Senate majority also allows Democrats to block Trump’s executive branch appointees, potentially leaving key positions unfilled or forcing the president to nominate more moderate candidates.

Executive powers remain intact

Trump retains broad constitutional authority that operates independently of Congress. As commander in chief, he controls military operations, though Congress can attempt to limit war powers through resolutions that face the veto override hurdle.

The president has issued nearly 300 executive orders since January 2025, more than any president in a two-year period since Harry Truman. More than 30 invoke emergency powers, with six declaring new national emergencies.

The White House has spent months preparing for Democratic control, developing plans to advance the president’s agenda through executive action on immigration, tariffs, housing costs and federal spending.

Among the executive actions under consideration are new tariffs on imports of critical minerals and wind turbines, tighter visa rules for international students and temporary foreign workers, and measures aimed at lowering housing costs.

A 2024 Supreme Court decision in Trump v United States significantly expanded presidential immunity, granting absolute protection for core constitutional powers and presumptive immunity for other official acts. Legal experts say this ruling has shrunk Congress’s ability to conduct oversight.

The impeachment question

Democrats have the power to impeach Trump with a simple majority vote in the House. The president was impeached twice during his first term but was acquitted by the Senate both times.

Impeachment conviction requires a two-thirds Senate vote, meaning Democrats would need 17 Republicans to join them to remove Trump from office – a scenario that appears highly unlikely.

Democratic leaders have been cautious about pursuing a third impeachment. Jeffries said his party has “not ruled anything in and not ruled anything out” on accountability, whilst Raskin argued that Trump is “very eager” for Democrats to impeach him and vowed not to “play into the game”.

Some Democrats have suggested impeaching Cabinet officials instead. Representative Sydney Kamlager-Dove has already introduced articles of impeachment against White House budget director Russell Vought.

Democratic legislative agenda faces obstacles

House Democrats plan to focus on reversing nearly $1 trillion in Medicaid cuts, restoring expired healthcare subsidies under the Affordable Care Act, ending Trump’s global tariffs, and stopping the war with Iran that began in February without congressional authorisation.

Jeffries told ABC News the party’s “day one plan” will focus on healthcare and “driving down the high price of groceries and gas and housing”.

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However, most Democratic priorities face two major obstacles: Trump’s veto and the Senate filibuster, which requires 60 votes to pass most legislation. This means Democrats will need to negotiate with Trump or find ways to attract Republican support.

The Trump administration’s response

The Trump administration is expected to assert executive privilege and refuse to comply with many congressional investigations, as it did during the president’s first term.

Senior officials including deputy chief of staff Stephen Miller and budget director Russell Vought have worked with the White House Counsel’s Office since April to identify actions Trump can take without congressional approval.

Trump told The New York Times he expects to issue vetoes “for a month or two” before reaching compromises with Democrats.

The president faces government funding negotiations before the new Congress takes office, with current funding expiring on 11 December. Senate Democrats could filibuster a spending bill at the risk of a government shutdown.

A constitutional test

The Los Angeles Times described the Democratic takeover as potentially “one final constitutional test for the Trump era, challenging the legislative branch to reclaim its role as a check on an increasingly powerful White House”.

However, legal experts note that the system of checks and balances makes it difficult for Congress to hold the executive fully accountable, particularly given the high bar for veto overrides and the expanded presidential immunity granted by the Supreme Court.

The result is likely to be two years of political gridlock, aggressive congressional investigations, and battles over government funding, with Trump wielding executive power whilst Democrats control the legislative agenda but lack the votes to override his vetoes.

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