Such disaffected groups have significant potential claims on federal and state government support. And these claims are potentially open to mobilisation by insurgent politicians, as both Trump and Sanders are now demonstrating.

The discontent of much of the electorate is not only driving distrust of government and politicians who are seen as part of the Washington establishment. It is one of the key factors contributing to sky-high rates of political polarisation in the country.

This could have crucial implications not just for the outcome of the presidential contest, but also for public policy and governance in Washington from 2017, given the significant prospect of gridlock where key issues, like immigration reform, have been put into the deep freeze because of differences between and within the parties. Indeed, in a political system that was built on achieving consensus, polarisation is precluding the development of a range of short- and long-term policy solutions in areas from education to infrastructure, all of which undermines the long-term economic vitality of the country.

While polarisation reflects the current levels of voter discontent, including growing divides over wealth and educational attainment that Trump and Sanders are proving skilful at tapping into, it is also driven by longer-term demographic and generational changes. Thus, one of the most notable features of the contemporary political environment is the Republican Party’s heavy dependence on white, older, southern voters, while its Democratic counterpart has a more disparate coalition of blacks, younger whites and new immigrants across the country, including the south, along the west coast and the northeast.

The last presidential election highlighted these stark partisan divides with Republican Mitt Romney winning a huge slice of the white electorate – almost 90 per cent of his support came from non-Hispanic whites. Yet, he still lost relatively narrowly to Obama, who had 95 per cent backing of blacks, over 70 per cent of Hispanics, and around two-thirds of Asian Americans.

The stark demographic, ideological and cultural cleavages in the US electorate appear to be intensifying at the moment when the electorate has become the most diverse ever. Nearly one in three eligible voters this year will be Hispanic, Asian or another racial minority. What this profound demographic shift underlines is that the US is on a trajectory to become, potentially around mid-century, a majority non-white nation. At the same time, there is rapid ageing of the electorate.

Elements of the Republican Party, as seen in the divisive anti-immigrant rhetoric of Trump, are challenged by the changing social landscape of the country, although some candidates such as Marco Rubio are promoting a more welcoming stance mirroring that of George W. Bush, who won 40 per cent of the Hispanic vote in 2004. With Trump winning in New Hampshire, there remains a significant prospect that he will continue to disproportionately set the agenda for the Republican race for potentially weeks to come, including in South Carolina on February 20.

Should this happen, it could further alienate key voting groups, including Hispanics. And as demographic shifts in population are working against Republicans, the failure of the latter to reach out more aggressively to Democratic-leaning constituencies will undermine the prospects for the eventual Republican nominee to win against former secretary of state Hillary Clinton, who remains likely to beat Sanders despite his New Hampshire win.

Andrew Hammond is an associate at LSE IDEAS (the Centre for International Affairs, Diplomacy and Strategy) at the London School of Economics