There is an old American saying, ‘politics should stop at the water’s edge’. It means foreign policy should be driven by a country’s national interests and values, not its domestic politics. But it’s a myth.

Britain’s vote to leave the European Union is one example of exploding this myth. Overnight, British citizens fundamentally altered the structure of their foreign policy. David Cameron had tried to use the referendum as leverage for concessions from Brussels, with the goal of addressing long-standing tensions within the ruling Conservative Party regarding EU membership. But he underestimated the British electorate’s growing anti-establishment sentiment. The Brexit vote was dramatic, but hardly unique. In this world of global networks and instant messaging, where almost anyone can draw millions of online spectators to the scene of an unfolding drama, public opinion is more dynamic than ever.

Existing assumptions about the world seem to be routinely overtaken by unexpected events. Political leaders who traditionally counted on public ambivalence regarding foreign affairs are finding it hard to keep up. No political leader can afford to ignore what his or her street is thinking, doing and tweeting, with democrats focused on the next election and autocrats fearing the next uprising.

Five years after political protests swept across the Middle East and North Africa, revolutions, counter-revolutions, crackdowns and civil wars have left hundreds of thousands dead and millions displaced. The mayhem enabled the rise of Daesh, which established a caliphate defined by its opposition to the modern secular world. Vladimir Putin, meanwhile, saw the 2014 revolution in Ukraine spiralling beyond his control and sought to undermine it, appropriating Crimea in the process. The US and Europe imposed sanctions in response, but the successful Sochi Olympics, combined with the Ukraine crisis, reminded the Russian people of the halcyon days of the Cold War. What political leader would change course with approval ratings above 80%? Putin, far more a gambler than a grand strategist, doubled down in Syria. He will be antagonist-in-chief for the next American president’s entire term in office.

Putin, the Syrian civil war and Daesh have been significant issues in the 2016 US presidential campaign, far more so than Brexit. Nonetheless, the political dynamic that powered Brexit is evident in the astonishing emergence of Donald Trump as the Republican presidential nominee. Trump embraced a neo-isolationist political credo of “America first”, which appealed to a narrow sub-segment of the population. He promised to construct walls and impose bans to keep immigrants at bay. He rejected multilateral trade agreements that, in his view, favour China and others who don’t play by accepted international rules. He called NATO obsolete and conditioned the United States’ alliance commitments on whether America’s friends were shouldering their fair share of the security burden. He even saluted Brexit as an effort by the people to take their country back.

Trump’s contest against former secretary of state Hillary Clinton quickly embodied the prevailing tension between two different conceptions of America’s global leadership role. Clinton, a strong internationalist, is an ardent believer in American exceptionalism. She sees the US as uniquely positioned to lead the world in solving pressing global challenges. Clinton helped set the table for the international agreement with Iran regarding its nuclear programme, arguably the signature achievement of the Obama administration, and promised to vigorously enforce it as president. She was an ardent supporter of the NATO intervention in Libya, concluding that the only way to protect the Libyan people from a vengeful leader was to create favourable conditions for Gaddafi’s overthrow. Her vote in favour of the Iraq invasion probably cost her the Democratic nomination and election in 2008.

“Putin, the Syrian civil war and Daesh have been significant issues in the 2016 US presidential campaign, far more so than Brexit”

On the other hand, Trump called the Iran nuclear agreement ‘one of the worst deals ever negotiated’, although he was more circumspect than other Republican presidential candidates over what he would actually do about it. Trump promised to restore respect for American power, calling Obama’s struggles with the Syrian civil war – in particular the red line he drew over the Assad regime’s use of chemical weapons – a ‘humiliation’. While he pledged to be tough and strong as president, he also promised to be more selective on US intervention. A Trump administration would not engage in nation-building. Trump riled the Republican establishment too by denouncing the Iraq War as a ‘big fat mistake’, and accusing George W. Bush of lying about Iraq’s weapons of mass destruction.

Given the shock of the 11 September attacks, Bush faced little political opposition when he declared a war on terror and developed an aggressive strategy of ‘with us or against us’ that illuminated a path from Afghanistan to Iraq. Obama represented a counter-narrative, leading a US prepared to find common cause with friends and constructively engage adversaries. By and large, Obama’s foreign policy mirrored what he offered on the campaign trail in 2008. And to a great degree, he delivered the foreign policy the American people said they wanted. He was unable to close the prison at Guantanamo, but he made the problem smaller. Forces remain in Afghanistan and Iraq, but as allies, not occupiers. Given his mandate to end wars and avoid new ones, Obama struggled to find a viable strategy in Syria. He declared war against Daesh but not Assad, and in so doing avoided placing large numbers of American troops in the middle of a conflict that plays into the narrative of an intractable war between Islam and the West.

Notwithstanding Trump’s populist appeal, underestimated ever since his campaign began, it’s not clear the American people are looking for a dramatic change. They continue to support American leadership in the world even if, after Iraq, they are wary of its costs. Confronting a world that seems to be changing dramatically with each passing day, the American public is most likely to stick with the foreign policy they know. But, as with Brexit, it’s the actual votes that count.

IMAGE CREDIT: CC / FLICKR – Matt Wade