THE science is settled: Trump can’t be stumped.

The controversial billionaire has an 87 per cent chance of defeating Hillary Clinton in November, and a 99 per cent chance of defeating Bernie Sanders.

That’s according to the Primary Model, a statistical analysis model developed by Stony Brook University political science professor Helmut Norpoth, which has correctly predicted the last five US elections since it was introduced in 1996.

It comes as voters in Hawaii, Idaho, Michigan and Mississippi have their say in the US presidential nominating race, with Trump picking up the latter two states.



The Primary Model relies on the presidential primaries and the election cycle as predictors of the vote in the general election, and Professor Norpoth says early primaries are a leading indicator of electoral victory.

Trump won the Republican primaries in both New Hampshire and South Carolina, while Clinton and Sanders split the Democratic primaries in those states.

“What favours the GOP in 2016 as well, no matter if Trump is the nominee or any other Republican, is a cycle of presidential elections,” he wrote on The Huffington Post.

“After two terms of Democrat Barack Obama in the White House the electoral pendulum is poised to swing to the GOP this year. This cycle, which is illustrated with elections since 1960, goes back a long way to 1828.”

Professor Norpoth says in a match-up between Trump and either Democratic contender, the Primary Model predicts Trump would defeat Clinton by 52.5 per cent to 47.5 per cent of the two-party vote.

Against Sanders, Trump would take 57.7 per cent versus 42.3 per cent.

Importantly, Professor Norpoth says that result even factors in Trump’s outrageous comments.

“Winning early primaries is a sign that a candidate has a favourable image,” he wrote in a recent question-and-answer session on reddit. “Whatever past gaffes or scandals might affect a candidate have been absorbed into that image by then.”

Trump was accused of dragging the presidential race into the gutter last week with a reference to his penis size, after rival candidate Marco Rubio made a suggestive comment about Trump having “small hands” at a rally.

“Trump has held pretty steady in the 30s,” Professor Norpoth says. “He does not seem to slip in approval for any stupid, silly, outrageous and offensive remarks. That alone is a new thing.”

This all assumes Trump, who has been hit with an onslaught of attacks from both rivals and the Republican establishment, wins the nomination.

Over the weekend, a secretive meeting of billionaires, tech CEOs and high-ranking Republicans — which included Apple’s Tim Cook, Google co-founder Larry Page and Tesla’s Elon Musk — put their heads together to work out a plan to defeat the real estate mogul.

And in an unprecedented attack last week, former Republican candidate Mitt Romney blasted Trump as a “fraud”. However, a new poll suggests that attack may have actually helped Trump, finding 31 per cent of Republican voters are more likely to vote for him because of Romney’s speech.

Professor Norpoth says he can’t predict the outcome of nomination contest. “But ask yourself, who has not got the nomination in at least the last 60 years who racked as many wins in the primaries as Trump? I can’t think of any,” he said.

In January 2012, Professor Norpoth predicted Barack Obama would defeat Mitt Romney with 88 per cent certainty, and around the same time in 2004 that George W. Bush would be re-elected with more than 95 per cent certainty.

The model pulls in data from every presidential election going back until 1912 — the year the primary system was introduced — to estimate the weight of primary performance.

“That year the candidate who won his party’s primary vote, Woodrow Wilson, went on to defeat the candidate who lost his party’s primary vote, William Howard Taft,” Professor Norpoth writes.

“As a rule, the candidate with the better primary performance, as compared to his or her strongest rival, beats the candidate with the weaker primary performance.”

Applied retroactively, the Primary Model has correctly picked the winner in every presidential election going back to 1912 except for 1960, when John F. Kennedy defeated Richard Nixon.

Professor Norpoth remains cautious, however. “I agree with Mark Twain,” he wrote. “Prophesy is good business, but it is full of risks.”

frank.chung@news.com.au