The Influence of War with Iran on US Mid-Term Legislative Elections

The Influence of War with Iran on US Mid-Term Legislative Elections

Over the past 100 years, the United States has never “lost a war” militarily or tactically against another nation. America’s withdrawal from Vietnam and Afghanistan resulted not from military defeat but from a shift in domestic political sentiment against war, which led to changes in which political party controlled government.

During the Vietnam War, President Lyndon B. Johnson of the Democratic Party escalated the conflict with large-scale troop deployments and was replaced in 1969 by President Richard Nixon of the Republican Party, who gradually reduced and eventually withdrew all US forces from Vietnam three years later. This led to the North Vietnamese Viet Cong taking control of South Vietnam, subsequently unifying the country as the Socialist Republic of Vietnam in 1976.

Similarly, regarding the US war in Afghanistan, then Vice-President Biden promised during his 2020 presidential campaign against President Trump to withdraw troops from Afghanistan, arguing the military mission had been accomplished. After winning the election, President Biden ordered a complete withdrawal of US forces within less than two years, an action that appeared rushed.

The greatest irony for America in Afghanistan was that after 20 years fighting the Taliban regime, whom the US held responsible for the September 11, 2001 terrorist attacks, the Taliban returned to power and seized all the military equipment and installations left behind by the US.

These two cases provide important reference points. American military withdrawals resulted more from domestic political sentiment turning anti-war than from battlefield defeats. So what of the current conflict with Iran?

The forthcoming electoral event is the US mid-term election on 3 November 2026, which will select all 435 House of Representatives members and 33 of 100 senators. The winning party will control the Speaker of the House, all committee chairs, and legislative agenda, effectively determining whether bills pass or fail. However, one crucial element not directly measured in mid-term elections is a confidence referendum on the sitting President. This year, this factor will prove decisive.

Based on 40 mid-term elections since the American Civil War in 1862, the sitting President’s party has lost 37 times and won only three times. This aligns with American democratic values favouring checks and balances between executive and legislative branches, or reflects voter dissatisfaction with the President’s performance. Historical data shows the President’s party loses approximately 26 House seats and four Senate seats on average in mid-terms. Given the Republican Party’s current majority of only three House seats and six Senate seats, the party risks losing its legislative majorities.

Given this historical precedent alone, President Trump and the Republican Party should be concerned about the November 2026 mid-term results. This concern intensifies if the war with Iran becomes protracted.

Determining Factors in the 2026 US Mid-Term Elections

The 2026 mid-term elections, like previous elections, will be determined by key factors including inflation and affordability, energy prices and fuel costs, immigration, economic conditions and employment, government spending and debt, taxes, and major social issues such as healthcare, social programmes, abortion, and public safety. Foreign policy, typically receiving limited attention, takes on unexpected importance here.

In this context, an extended Iran conflict poses significant risk to President Trump and the Republican Party. If the war concludes quickly before the campaign peaks between August and early November, its electoral impact would be limited. However, prolonged conflict would severely damage the Republican Party’s prospects. The Iran war would influence the 2026 mid-term elections through several key mechanisms:

1. Energy and fuel prices would directly burden American households. Trump’s defensive argument that the US currently achieves energy self-sufficiency and is even a net exporter lacks effectiveness because domestically produced oil still follows global market prices. The US has no fuel price subsidy mechanism;

2. Beyond direct energy price impacts causing inflation increases, Persian Gulf countries supply 30 percent of global ammonia and 50 percent of global urea traded worldwide—essential inputs for non-organic fertiliser production. This creates even greater inflationary pressure. For the Republican Party particularly, rural agricultural regions constitute a strong MAGA/America First constituency base that secured victory in the 2024 elections;

3. US economic growth and employment will slow both from elevated energy prices and inflation, and because the US Federal Reserve will be reluctant to reduce interest rates whilst inflation risks persist;

4. A prolonged war will increase US defence spending, raising government deficits and debt—extremely unpopular among the American public, particularly among Republicans and Trump supporters who won the 2024 elections promising to reduce spending, deficits, taxes, and government debt.

In addition to these typical mid-term election issues, prolonged conflict would trigger the same domestic political sentiment shifts that affected Vietnam and Afghanistan, substantially weakening Republican electoral prospects.