The parallels are impossible to ignore. In both the U.S. and U.K., populist campaigns stoked by economic and immigration anxiety have taken on the ruling elite of two major political parties and scored conventional wisdom-defying victories. Posed in a certain light, the Brexit effort and Donald Trump’s presidential candidacy appear to be twin causes, feeding off recognizable political grist. But even as the forces driving their respective successes draw on some of the same innate social movements, the hurdles facing Trump’s stretch run to the White House are much different – and likely more difficult to clear – from those now surpassed by the Brexit campaign. Among them: Washington vs. Brussels Much of the frustration fueling Trump’s success is aimed at the national political establishment. Supporters rail against career politicians in Washington, D.C., saying their interests are increasingly divorced from those of the voters who put them in office. As the success of the tea party makes clear, this is a potent political message – one being harnessed now by the Trump campaign. But for all the frustration among Trump’s backers, imagine their fury if the object of their ire was not an American city but a foreign capital. The seat of EU power is in Brussels, Belgium, allowing “leave” campaigners to make the case that British policy was being dictated from abroad. Trump has made clear he wants to steer the U.S. away from the influence of foreign alliances, but he cannot draw on such a clear line – and provocation – as available to “Leave” organizers, who harped on fears that British sovereignty was on the line. A candidate vs. an issue Most American voters in November will cast a ballot for one of two major party candidates. But even if the piece of the U.S. electorate that rates its desire for Trump’s brand of border security as their top priority outpaces those who prefer Hillary Clinton, there are a multitude of unrelated issues that will likely drive their decisions. A February Gallup poll found that only the economy, national security, jobs and health care rated as “above average in importance” across the political spectrum. After that, the relevance of a candidate’s positions varied. So while Trump has undoubtedly struck a chord on immigration with his supporters, it’s unclear how many voters will walk into their polling place in November with solely that question and its implications in mind. For the “leave” campaign, the matter was much simpler. They had one question to press and considerably less concern about the doings of the well-known and polarizing political figures pushing their case. Trump, meanwhile, is not just selling his positions but his candidacy. In choosing whether to vote for Trump, voters will be making more than a binary choice – they’ll have to consider his position on issues, his preparedness for the Oval Office and their opinion of the man himself – all while being presented with an alternative major party candidate in Clinton. Referendum vs. indirect election The most apparent distinction between Thursday’s Brexit vote and the coming U.S. general election is their reliance on two very different democratic mechanisms. The U.K.’s decision to leave the European Union was made via popular referendum. That exercise of “direct democracy” cut out the familiar barriers – in this case, parliament and the prime minister – and put the decision squarely on the voters. The American presidential system, by its nature, puts more space between their will and political action. That space, occupied in the general election campaign by the electoral college, offers a unique benefit to the more organized, strategic campaign. So while victory in, say, Ohio, by one vote or 1 million, could decide the race, simply winning the popular vote nationwide won’t be enough to carry Trump or Clinton to victory. Demographics Both the “leave” campaign and Trump’s presidential bid have been powered in large part by concerns over mass immigration. But if the two movements are pulling support from similar wells of political discontent among non-Hispanic white voters, the British side enjoyed a proportionately deeper reserve. According to the CIA World Factbook, the British population was more than 87% white in 2011. Other estimates put the ratio at higher than 90%. Meanwhile, a Pew survey from earlier this year found that “the U.S. electorate (in 2016) will be the country’s most racially and ethnically diverse ever.” More than 30% of eligible voters will come from a racial or ethnic minority group. The non-Hispanic white vote is expected to make up 69% of eligible voters, down from 71% in 2012. For Trump, who has alienated large swaths of minority voters with his immigration rhetoric, victory will likely have to come from securing a large portion of a diminishing slice of the electoral pie.