'Power of the purse': What Trump stands to lose in US midterm test

The 2026 United States midterm elections will be a crucial test of Donald Trump's political strength, with Democrats hoping to regain control of Congress and Republicans seeking to defy the historical tendency for a president's party to lose ground halfway through a term.

The November elections will determine control of the House of Representatives and could reshape the balance of power in Washington for the final two years of Trump's presidency.

The first midterm primaries were held in March and have continued in recent months, with Alaska, Florida and Wyoming holding their primaries this week.

For Democrats, the November midterms offer an opportunity to demonstrate that dissatisfaction with Trump can translate into electoral gains and to begin rebuilding the party ahead of the next general election in 2028.

For Republicans, the elections will test whether Trump's political strength remains sufficient to protect the party from the historical midterm backlash that has affected many previous administrations.

And for Trump himself, a Democratic-controlled House could mean substantially greater scrutiny, investigations and political resistance during the final years of his presidency.

Wesley Widmaier, a professor at the Australian National University Department of International Relations, told SBS News an overall loss for Trump would restrict his influence.

"The House controls the power of the purse and is where budgets originate in the American system. A Democrat win would mean a loss of a lot of control for Trump," he said.

Ultimately, the midterms could provide the clearest indication yet of whether the political momentum in the US is shifting away from Trump and the Republican Party — or whether Republicans can defy the historical pattern and maintain their grip on Congress.

Why are midterms significant?

Every two years, US citizens elect all 435 members of the House of Representatives, while roughly one-third of the Senate is elected.

The two bodies have separate but complementary functions.

The House of Representatives has the special power to initiate tax bills and to impeach officials, while the Senate approves presidential appointments, such as judges and cabinet members.

Unlike in Australia, voting in US elections is not compulsory, and midterm elections — those held between presidential elections — tend to have lower voter turnout and less media attention.

But Widmaier said they still have significance for US politics and decision-making.

Historically, the president's party tends to lose ground in the House during midterm elections, he explained.

"People get excited about a potential candidate in the main year election, then there's always some wearing off of the bloom," he said.

The Democrats need to gain four seats in the House of Representatives to outnumber Republicans. Analysts are largely predicting the Democrats will win enough seats to claim victory, but what they could do with that power remains to be seen.

What does a loss mean for Trump?

A Democratic victory in the House would significantly change the political environment surrounding Trump.

"Most recent US presidents have tended to suffer quite a setback from their party in the House of Representatives two years into their presidency," Brendon O'Connor, a US politics expert from the University of Sydney, told SBS News.

"Obama called it a shellacking when he lost in 2010."

Republicans lost about 40 House seats in the 2018 midterms under Trump.

O'Connor said this allowed the Democrats to oppose policy more strongly and hold Republican leaders to account than in the first two years of Trump's presidency. Trump was impeached twice by the House in that time.

O'Connor expects a similar period of heightened scrutiny if Democrats regain the House, predicting that the activities of Immigration and Customs Enforcement, Trump's financial affairs and his involvement in cryptocurrency would be scrutinised.

Trump would also lose the "power of the purse", making it harder to spend big on election promises, and would face a Democratic-controlled House, likely hostile over spending and budgets.

Gerrymandering makes the House harder to predict

One of the biggest complications for the 2026 House elections, Widmaier said, is the redrawing of electoral boundaries.

The term 'gerrymandering' is used to describe the practice of state legislators redrawing congressional boundaries, often to give the ruling party an advantage, which most states allow.

Unlike Australia, where electoral boundaries are generally determined through independent electoral processes, US congressional districts can be heavily influenced by partisan politics.

Electoral boundaries are typically redistricted every 10 years when US census data is released; however, Republicans and Democrats have both pursued changes to electoral boundaries, creating a complicated political map ahead of the midterms.

"The most interesting thing about the House of Representatives races is the gerrymandering," O'Connor said, arguing that changes to electoral boundaries in states including Texas and California make it harder to predict how national shifts in voter sentiment will translate into seats.

As a result, even if Democrats perform strongly nationwide, their gains may not be as dramatic as a straightforward comparison with previous elections would suggest.

The Senate remains crucial

Democrats also have a chance of winning the Senate, according to O'Connor and Widmaier, although any Democratic majority is expected to be narrow.

A Democratic takeover of both chambers would represent a far more substantial shift in Washington, potentially allowing Democrats greater control over legislation and congressional oversight.

But if Republicans retain the Senate, the political battle between Congress and the White House could become the defining feature of the final two years of Trump’s presidency.

The outcome will also determine how much room Trump has to pursue his policy agenda without facing sustained resistance from Congress.

Widmaier said that the midterms don't always predict a successful presidential candidate or party, looking to the recent example of former US president Joe Biden, who won the 2022 midterms, but his party subsequently lost the 2024 election under Kamala Harris.

But in general, he believes parties tend to take the approach that "it's better to just keep winning".

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