When the cameras rolled for the third presidential debate this week, all signs were pointing to a victory in the United States presidential election for Democrat Hillary Clinton over Republican Donald Trump. But not, necessarily, a landslide – a victory so overwhelming it constitutes a turning point in how people conceptualise the political terrain.
One popular definition is that an election is a landslide when the margin of victory is 20 percentage points or more. That hasn’t happened in America since 1984, when Ronald Reagan defeated Walter Mondale by winning 49 out of 50 states, 525 electoral votes to 13. But even then, Reagan didn’t get past 60 per cent of the popular vote; he won 58.77 per cent. Over the past two decades, the greatest popular margin of victory was Barack Obama’s 7.34 percentage points over John McCain in 2008 – which is greater than Clinton’s average poll margin over Trump now.
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The ghosts of 1968: why Donald Trump is not the new Richard Nixon
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The reason why genuine blowouts have become inconceivable is that the US electorate has sorted itself into ever more rigid tribal identities, so that voting for a Democrat or a Republican becomes instinctual, regardless of the particular candidates. And even in the case of the most famous landslides – Franklin D Roosevelt over Alf Landon, of 61 per cent to 36.5 in 1936; Lyndon Johnson over Barry Goldwater, by 61 per cent to 38.5 in 1964; Richard Nixon over George McGovern, by 60.7 per cent to 37.5 in 1972 – US political parties have proved quite resilient in the aftermath.
Although every time it happens, pundits tend to predict the losing party will “go the way of the Whigs” – the last major political party to die out, in 1854.
But the US “first past the post” electoral system, in all its laws, conventions and codes, is rigidly structured to preserve the existing two major parties.
A good example is what happened after the 1964 election, when Goldwater, the most conservative major-party candidate to that date, lost. The New York Times's marquee columnist, James Rest, said Goldwater "had wrecked his party for a long time to come". But then, in the off-year congressional elections of 1966, the Republicans gained back most of their losses; in 1968, Republican candidate Nixon won the presidency. In the social chaos of the 1960s, the sort of conservatism the pundits dismissed in 1964 proved to be strikingly popular with the electorate.
Here’s what we can expect if Trump loses, even in a landslide: Republican leaders will hit the reset button. They will join together in pronouncing that Trump lost because he wasn’t a “genuine” conservative. Republican leaders such as Paul Ryan, Ted Cruz and Marco Rubio will fight among themselves for the mantle of this putative “true” conservatism. They will also adopt some portion of Trump’s message and style.
And if history is any guide, one of them – or some player on the horizon not yet recognised – will emerge as surprisingly competitive in 2020. Don’t count the Grand Old Party out yet.

