Republican presidential candidate Donald Trump speaks during a rally in Spokane, Wash., Saturday, May 7, 2016. The presumptive GOP presidential nominee told people in Spokane that he'd return to the Northwest during the campaign "because we are going to take the state of Washington." (AP Photo/Ted S. Warren)

Republican presidential candidate Donald Trump speaks during a rally in Spokane, Wash., Saturday, May 7, 2016. The presumptive GOP presidential nominee told people in Spokane that he'd return to the Northwest during the campaign "because we are going to take the state of Washington." (AP Photo/Ted S. Warren) Ted S. Warren

DONALD Trump's mother, Mary-Anne MacLeod, comes from the Isle of Lewis in Scotland. So does my great grandfather, John MacLeod.

Despite our frighteningly proximate DNA and our similar hair colour, I'd rather not have Trump in the White House. Neither would many Americans, yet it is now very likely that the Republican nominee will be the next American president - and he could win in a landslide.

The political establishment underestimated Trump's campaign, and their naivety is coming back to haunt them. When I was an army officer, we were taught that the greatest error was to underestimate the enemy. If one underestimates the enemy, then one will attack with too few resources and be soundly beaten - like America in Vietnam, Russia in Afghanistan and the Germans in Moscow.

Right from Trump's first days on the campaign trail, those opposing Trump have radically underestimated the threat. The Huffington Post even put him on its entertainment page. It did not analyse the opposition accurately, and the threat grew.

Over the past few months, the media moved from treating him like a joke to assuming that he would "fall after Super Tuesday". He didn't. Then they claimed that his comments on abortion would put a stop to him. They didn't.

Later, losing Wisconsin was supposed to be a turning point - but it certainly wasn't. Eventually it was assumed that Cruz and Kasich would team up and force a brokered Convention. They didn't, and Trump has won the Republican nomination.

Now the media, having failed to learn its lesson, says Trump will be caught out by his tax affairs, or will fail to "get out the vote", or that the polls show that both Sanders or Clinton could beat him.

The underestimation continues, and ignores the fact that this November, Americans aren't just voting on the president. They are voting for the Senate, the House, many local governors, judges, prosecutors, sheriffs. Even though dog-catchers are no longer elected, many municipal positions are.

Republicans will turn out to vote for all the other offices. While there, they will be faced with the choice of holding their nose and voting for Trump, or, one presumes, Hillary Clinton.

Democrats are kidding themselves if they think Republicans opposed to his candidacy won't vote for Trump when it comes down to the wire. Consider this: in the 2008 North Carolina Democratic primaries, 38 per cent of Clinton's supporters said they'd vote for John McCain over Barack Obama and 12 per cent said they would not vote at all. When election day came around, most shifted their view and voted for Obama.

The same shift is happening within the GOP now. Trump's approval rating is rising. Republican anti-Trump forces are retreating like Napoleon from Moscow, leaving bodies in their wake. Opponents such as Paul Ryan are casting around to find reasons to support Trump.

Winning and losing elections in America is not about pinching votes from the other team. It is getting your team out to vote. In the US, voter turnout hasn't exceeded 60 per cent for nearly 50 years. In 1968, 60.7 per cent of eligible voters actually managed to drag themselves out of bed and exercise a right that people had fought and died for. In 1996, less than 50 per cent bothered turning up.

Getting out your own voters is far easier, and far more important, than pinching votes from the other side. In both 2008 and 2012, Obama ran a massive "get out the vote" campaign, inspiring many first time voters with the promise of hope, change and making history by electing the first black man to the White House. Voter turnout in 2008 was the highest since 1968.

Clinton, on the other hand, does not inspire that level of emotion. The so called "woman card" that she plays is not motivating women either. In the Iowa caucus, only 14 per cent of women under 30 voted for Hillary; in New Hampshire it was around 10 per cent. Young women went for the 'old white guy' - Bernie Sanders.

Trump is accused of having a "woman problem", but so does Clinton. Both Clinton and Trump are widely unpopular, but Trump has one advantage: he is inspiring first-time voters to turn out on polling day.

Trump is gaining votes in the "rust belt" from people who would not normally vote Republican, or even vote at all. A recent poll even had Trump him behind Clinton, by only 0.3 per cent. His momentum is upward. Do you see where this is heading?

Clinton will get fewer votes than Obama. Trump will get out far more first-time voters than the Republicans have ever achieved before, while regular Republican voters will hold their noses and punt for Trump.

Unless the left stop dreaming up reasons for Trump to lose, and start campaigning like he might win, the 2016 election will be the landslide for Trump.

Andrew MacLeod is visiting professor in the Policy Institute at Kings College London, a corporate director in the US and a former UN official.