Conventional wisdom in the United States posits that American voters don’t cast their votes based on foreign policy and that US politics should stop at the water’s edge. History, however, shows some exceptions — and this year may be yet another.

Forty-four years ago, President Jimmy Carter ordered a boycott by US athletes of the Moscow Olympic Games over the Soviet Union’s invasion of Afghanistan. Americans were deprived of seeing their athletes compete on the world stage just three months before a presidential election. Carter lost that election, and while it’s hard to tie his loss directly to the Olympic disappointment, it did provide a jumping off point for Republican nominee Ronald Reagan’s general election campaign and pointed criticism of Carter’s foreign policy just weeks before voting day.

The battle between President Joe Biden and former President Donald Trump is effectively tied — the RealClearPolitics polling average gives Trump a 1.1 per cent advantage over Biden. Foreign policy could once again make the difference.

Beyond the election itself, the big media stories in the United States are foreign policy-focused. Protests on college campuses over the war in Gaza are front page news. Also subject to daily news updates are the Russian invasion of Ukraine, attacks by Yemeni Houthis on shipping in the Red Sea, unchecked immigration across America’s southern border and the flood of cheap manufactured goods from China.

These issues have already become deeply politicised. For example, the Biden administration’s responses to the war in Gaza are two tracked — in public, criticism of Israel and Prime Minister Benjamin Netanyahu over the humanitarian situation, and behind the scenes, strong material support for Israeli military efforts. The public criticism is meant to appeal to voters in Michigan, a battleground state, and younger voters, traditionally a key Democratic constituency, who are skeptical of Israel’s moves against Hamas (see the campus protests).

On Ukraine, the Republican-controlled House of Representatives only approved massive new aid to the country defending itself against Russia’s invasion after Trump gave a green light (or at least not a red light) to the effort. Speaker Mike Johnson (R-LA), who took the belated but courageous step of bringing the aid to a vote, may yet lose his leadership position over the issue as Republican isolationists like Rep. Marjorie Taylor Greene (R-GA) continue to attack him.

President Biden’s poll numbers are at historic lows for any US president. His dismal approval ratings began in August 2021 when his withdrawal of US forces from Afghanistan turned into a catastrophe. Trump has pounded away on this and Biden’s other perceived foreign policy failures, asserting that if he had been president, Russia would not have invaded Ukraine and Iran would not have launched missiles and drones at Israel.

The biggest challenge to the relatively strong US economic recovery may be China’s effort to revive its own economic growth by flooding the global market with steel, cheap solar panels, electric vehicles, and other manufactured goods. Seeking to avoid a spike in the already massive trade deficit with China, Biden sent Treasury Secretary Janet Yellen to plead with Xi Jinping to promote domestic Chinese consumption instead, a move that is doomed to fail.

Biden and Trump are offering competing tariff plans to address the threat from cheap Chinese manufacturers. Trump has proposed a global tariff of ten percent and more than 60 per cent on Chinese products. Biden has responded with plans to ban Chinese electric vehicles and other products. Both candidates are in favor of banning the Chinese-owned social media app, TikTok, although neither seems enthusiastic about the project, with Biden fearing the anger of millions of American TikTok users, and Trump, the wrath of wealthy donors.

Biden campaigned effectively in 2020 by saying he wanted to return to “normal” American foreign policy, as a way of contrasting his approach with the chaos and drama of the Trump years. But now a string of foreign policy failures and intractable dilemmas has made that message unusable. Trump’s emphasis on “strength” — while not providing actual policy details — may be the more effective message in 2024.

US friends and allies around the world are rightly concerned about another Trump administration, with his erratic, transactional and personal relationship-based approach to global affairs. Joe Biden can head this off, but not without getting a foreign policy win or two before the election. Can he bring the Gaza crisis to a close and stop Houthi attacks on commercial shipping in the Red Sea? Can he divert China’s massive export machine? Can he use the new military aid provided by Congress to give Ukraine a win against Russian forces? His reelection will depend on producing positive answers to at least one of these questions.