Can Congress stop Trump from restarting the war against Iran?

Apart from the Democrat Party, Vice President JD Vance was the winner of the midterms in the US. It set him free to distance himself from an unpopular war against Iran and prepare for the 2028 presidential election as the Republican candidate to replace President Trump who cannot run again.

Donald Trump is now officially a lame duck president, and the immediate problem of war and peace is if Trump carries on regardless as if the rejection of the Iran war by the American people were water off the back of a duck rather than a vote of censure.

Some commentators suggest that President Trump still has a free hand in foreign policy and as commander-in-chief he does not need congressional approval to engage in war, but the interplay between politics and law in the workings of the US constitution is a lot more complicated.

You would think that the resounding rejection of the war against Iran in midterm elections to the US Congress is an important constraint in the American system of checks and balances typical of the American constitution, and you would be right. The requirement to hold congressional elections two years into a four-year presidential term is primarily a political check on presidential power that is supposed to give the executive pause for thought about its overall direction including whether to continue a war – but not one without any legal teeth at all.

The president is commander in chief but only Congress can decide to go to war. Having midterms halfway through a presidency is a democratic check on a wayward president. According to Trump’s MAGA base he had gone off the main plank of his election pledge to keep the US out of foreign forever wars.

The midterm results are supposed to give the president and vice president pause for thought. Vance did not have to pause long. He had been against the war with Iran beforehand but not as free to talk as after he was proven right about its unpopularity. When it became clear the Republican Party suffered its worst defeat since George W Bush lost both the House and the Senate in 2006, he was ready with a four-point plan to restore support for himself and his party.

The four things the party needed to do to win back voters he said in a lengthy post on X were: to end the war with Iran, focus on the cost of living and inflation, put American first and change America’s relationship with Israel.

Trump agreed with Vance’s political diagnosis that “the reason why we lost is the war.” However, whether he will follow his vice president’s prescription is a separate issue. Trump is not a candidate for president in 2028 and may choose to ignore the wishes of the American people.

After the new Congress is in place in January, he may find that a determined Congress to end the war against Iran difficult to withstand if his vice president is openly against the war. Vance was elected to the presidency with Trump and unlike members of the cabinet cannot be dismissed. If he and Trump fall out over the war and Vance can swing enough Republican congressmen to vote with the Democrats to stop the war, they could cancel out the president’s ability to veto any Congress legislation to stop funding it or stop it altogether.

The Iraq war precedent

There is a precedent for an attempt by Congress to stop a war. It was during the second term of George W Bush when a Democrat majority Congress was elected on an anti-war platform in the November 2006 midterms and attempted to stop the unpopular war in Iraq. The Democrats had campaigned against Bush’s Iraq war and won a majority in both Houses of Congress

In March 2007 Congress passed funding legislation on condition requiring troop withdrawals from Iraq, but Bush vetoed the legislation and Congress was unable to override the veto as it required a two thirds majority in each House.

The difference in 2026, however, is that Vice President Vance is dead against continuation of the war on Iran, as are a number Republican congressmen and women who feel they cannot politically ignore the unpopularity of the war. As president of the Senate, Vance and other Republican members of both Houses may join forces with the Democrats to make up a two thirds majority in the House and Senate and thereby override any presidential veto.

As for the Iranians, they are over the moon with the result of the 2026 midterms, but know that Trump has the power and the inclination to resume the war at any moment and has assembled an armada in the region ready to strike again and may do so between now and the swearing in of the new Congress in January. If he does it would be a slap in the face of the American electorate and his vice president as well as the rest of the world.

That broadly sums up the state of affairs after the midterms in the US. Having inflicted Trump on the world, American democracy repudiated him over an unpopular foreign war. No more far away forever wars he promised his MAGA base, and they are intent on holding him to his promise.