1) Hillary Clinton, odds-on favourite to be Democrat nominee, is terrified of Trump. Forget all her bullish rhetoric, she now knows that in a straight fight for the White House, he'd be the worst kind of vicious, smart, unpredictable and populist opponent. Look how she instantly backtracked on branding him anti-women when he retaliated by going nuclear on Bill Clinton's infidelities.
2) Trump is utterly fearless. Punch him and he'll punch you harder back. He's confronted everyone and everything from China and ISIS to John McCain and the Pope - and done so with an unshakeable verve and gusto which has had even his most bitter enemies shaking their heads in silent appreciation.
3) He's not Ted Cruz. If you think Trump would be a dangerous president, then trust me, he's not even first base of menace compared to the extreme right wing zealot from Texas. Consider their relative positions on illegal immigrants: Trump wants a wall to stop more of them pouring into the country; Cruz wants every one of the current 12 million illegal immigrants living in America deported. One is a more draconian version of existing policy, the other is cruel, inhumane madness.
4) He's not Marco Rubio. As much as desperate GOP chiefs are now trying to big up the pint-sized, baby-faced senator, the truth is that he comes over as an inexperienced, amateurish little nerd who can't even drink a bottle of water without looking weird. Hillary would eat him for breakfast and spit him out for lunch.
5) Trump calls a spade a spade. There is, whether you love him or loathe him - and the entire world now appears to be firmly locked into one of those two camps - an indisputably refreshing candour to his public speaking. Trump doesn't care for politic niceties, he just calls it how he says it. That plain-talking is resonating powerfully. Americans are fed up with Washington types spewing politically-correct platitudes whilst talking and behaving entirely differently behind closed doors.
6) He stands up to the media. I was filming a documentary in Texas and Florida last week and was struck by how many people in those states cited to me Trump's refusal to be dictated to or trampled on by the news media, both TV and print, as a reason they would vote for him. He's even waged war with Fox News, something no other Conservative candidate would have previously ever dared to do. By doing so, he's reinforced his independent 'heroic outsider' credentials.
7) He's paying his own way. Trump's repeated reminder that he doesn't need donor cash because he's so loaded himself is a powerful asset. The message is crystal clear: 'I can't be bought.' Compare and contrast to Hillary Clinton, who spends much of her time taking big cheques from the likes of Goldman Sachs. This will be a huge battleground if the race turns out to be a match-off between the two of them.
8) He works hard and has been massively successful - the very currency of the American dream. Nobody can doubt that Trump puts the hours in, displaying extraordinary energy for a guy who lives off three hours sleep a night. Running for president is tough. But so is president, as Barack Obama's grey hair can testify. Trump is also a brilliant negotiator, and half the battle in politics is having the ability to do deals. He's done it all his life, and been transparently skilled at it.
9) He stands up for regular Americans. They see in Trump someone who will fight their corner. Hence his carefully crafted comment last night, 'I love educated people and I love poorly-educated people'. I've walked around the streets of New York with Trump and he has an almost mesmeric appeal to working-class blue collar Americans despite his immense wealth. That's because he never talks down to them, instead he trashes those like the bankers of Wall Street who he slams for 'wrecking' the livelihoods of ordinary Americans. Trump, to them, is Robin Hood not the Sheriff of Nottingham.
10) He has a great potential First Family. Trump's wife Melania is beautiful, elegant, and a legal immigrant who represents the very epitome of the American dream. As she said last night about her path to U.S. citizenship: 'I followed the law, I never thought to stay here without papers.' Trump's children are equally impressive, especially his daughter Ivanka who I know well and is a highly intelligent, classy young working mother. Optics matter in presidential races and the Trumps look great standing together on a podium.