A senior advisor to the Leader of the Islamic Revolution has said the “real winner” of the US midterm elections was Iran, which has successfully shifted the costs of war onto American soil, as Democrats swept both chambers of Congress in a major rebuke to President Donald Trump.

Mohammad Mokhber wrote on X that Trump “did everything possible” to secure victory for his Republican Party but was “slapped by his own people” in the midterm elections.

“The real winner of this arena was Iran, which transferred the cost of the war into America,” he said.

The senior Iranian advisor warned Trump that continuing with his “failed policy” would squander what remains of US credibility “thanks to the blood of the martyrs and by the hand of the Iranian nation and the Resistance Front.”

Democrats won control of both the House and Senate in Tuesday's midterm elections, with the party flipping Senate seats in Republican strongholds including Texas, Kansas, South Carolina, Iowa, Ohio and Maine.

Democrats win both chambers of Congress in major midterm blow to Trump

The war against Iran also emerged as a significant source of discontent, as the conflict drove up gasoline prices and intensified concerns about the cost of living.

The US media reported that voters’ frustrations over high energy prices and inflation, caused by the war against Iran, contributed to the Republican defeat in the congressional elections.

President Trump acknowledged to US media that the war against Iran had “a certain impact” on his party’s performance.

Other Iranian officials also weighed in. Parliament Speaker Mohammad Baqer Qalibaf said Americans had said “no to war” through their votes.

“Conscience or the cost of living, Americans said NO TO WAR, and we endorse this message,” he posted on X.

Qalibaf, who is also Iran’s top negotiator with the United States, warned that if Washington betrays the American public’s will, it will learn that “NO comes with a Nightmare.”

The Democratic control of Congress is expected to constrain Trump’s legislative agenda and open the door to intensified oversight of his administration during his final two years in office.