The midterm elections are coming, in early November, when the full 435-seat House of Representatives will be up for grabs, along with 33 Senate seats.

And, historically, midterms are bad for US presidents. It’s a time when the euphoria from presidential campaigns has wound down, with promises and expectations inevitably unfulfilled.

Trump in fresh media blitz as midterm elections loom

The populace have typically used the midterms to lodge complaints; even if they can’t get at the president, they’ll go after his party.

In 2010, two years into his first term, then-president Barack Obama lost an incredible 63 seats in the House.

The Republicans only hold a 240-195 seat lead to the Democrats, which means the latter need to swing 23 Republican-held seats to win 218 – the number needed to fully control the House of Representatives.

Coupled with the fact that the average loss of seats by the party in power during midterms is 33, there’s a good chance the Republicans will lose their majority in the House of Representatives and possibly the Senate.

If the Republicans lose their majority in both upper and lower chambers, gone will be the days where Trump does anything he wants. There’ll be less room for chest-thumping bravado and more need for rational policymaking and diplomacy.

Trump would have to change his approach to adopt a more moderate tone: where before he could command, he would have to negotiate – with other countries, and within his own.

Beyond the midterms, the trade war doesn’t have a long shelf life and Trump doesn’t have a great shot at staying in power.

Watch: US-China trade war – day 105 and counting

In another two years, his own seat will be up for grabs in a new presidential election. Two years of Americans getting pummelled by tariffs won’t improve public opinion.

For the next election, the Democrats have a roster of visible superstars who are still gaining influence. The most powerful hopeful among them, Hillary Clinton, may run again and she doesn’t approve of trade wars.

Clinton has made clear that any trade war is a negative for the US, famously noting from as far back as during her election campaign that “we went down that road in the 1930s. It made the Great Depression longer and more painful”.

Ultimately, as analysts like Ben Rhodes, former adviser to Obama, have warned, the US won’t be able to win or sustain a trade war with China. In addition to bad economics, it’s a simple matter of how politics operates in the two countries.

If America does something that hurts millions of Chinese citizens, President Xi Jinping can weather that with a free hand.

Popular voting as an accountability mechanism doesn’t exist in China, but it does in the US.

When China retaliates and hurts millions of American citizens, the American people will respond by voicing their discontent towards their government through votes, at which point the US will have to back down.

Alibaba’s decision to drop plans to bring about a million jobs to the US has been one visible blow as a result of the trade war. (Alibaba owns the South China Morning Post.)

Key allies to the US aren’t happy at this time, either. Trump has isolated the US from its allies by stepping up tariffs with Canada and Europe.

With its allies alienated, the US is effectively alone in the ring with China, which will weaken its punches.

Trump’s trade war is a vanity project born of a protectionism that isn’t appropriate for a globalised world.

To be clear, there are some drawbacks to globalisation. How to keep capital and production within a country (effectively, how to make companies invest in the citizens of the country where these companies are based) remains a slippery question and much room remains for governments to step up controls.

But tariffs encourage protectionism, which also hurts countries in a global economy as nations are prompted toward self-sufficiency and suffer from less trade and weaker economic growth.

It was the realisation of this idea in the 1980s that prompted China to abandon its insistence on producing everything it needed on its own and open its borders, ushering in a new era of prosperity on the global stage.

But, where China has learned from its history, it appears the US is due for another lesson.

Anson Au is a scholar and writer whose work covers culture, health and politics. He is currently a visiting scholar at the Seoul National University Asia Centre and at Yonsei University, as well as a PhD student in sociology at the University of Toronto.