Donald Trump falls to Earth with a bump

Republican presidential candidate Donald Trump greets the crowd after speaking to supporters at a campaign stop Image copyright Getty Images

Who knew it? Newton was right; there is such a thing as gravity after all.

I'm not much of a scientist, but I had, well, started to doubt him. I thought maybe he hadn't got it right with the whole thing about the apple falling.

After nine months of the most improbable act of levitation ever seen outside of a circus or a weightlessness laboratory, the blond sorcerer has come down to earth.

No, he didn't reach terminal velocity. And as falls go, it wasn't that serious. He's got a few scrapes, and maybe that over inflated ego has had some of the air knocked out. You could hear the hissing sound from miles away. But a fall it has been.

And that is remarkable, because for nine months now it has seemed that Donald Trump could say and do whatever he liked without there being consequences. Disproving another law of physics: it seemed that an action, in his case, no longer provoked a reaction.

And what made mere mortals fall heavily, just seemed to set Mr Trump on an ever rising trajectory. Insult Mexicans, the polls rise. Have a pop at POWs, the crowds yell for more. Mock the disabled and the audience rock with laughter. Offend Muslims and his supporters say 'Hell. yeah!'.

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The laws of political gravity had been suspended - and the Washington soothsayers were left scratching their heads.

But then he took on women. Well to be strictly accurate he had taken on women before, with seemingly no ill effect.

You'll recall his comments to Rolling Stone magazine about Carly Fiorina's appearance - something to the effect of how was anyone going to vote for a woman with that face.

And then there was Megyn Kelly, the brilliant, sharp, meticulous presenter on Fox News who had the temerity to ask Mr Trump a finely honed question on his attitude to women a few months back.

Image copyright AP
Image caption Megyn Kelly asked Trump a "horrible" question

What she got in return from the property billionaire was the clear insinuation that she had only asked such a "horrible" question because she was menstruating.

Maybe that put a doubt in some people's minds. But then a few things came together in quick succession, and - let me go all Doctor Seuss here -

With a big kerrthump,

And a mighty bump,

Fell Mr Trump

Right onto his rump.

The insulting photo of Heidi Cruz, the suggestion that women should be punished for having an abortion if it is outlawed, Mr Trump standing up for his campaign manager when he is charged with assaulting a female journalist, crystallised into his poll standings falling too.

Image copyright Reuters
Image caption Is Cruz more trustworthy than his opponent?
Image copyright Reuters
Image caption For Cruz, the Wisconsin result is a much-needed boost

And so Wisconsin is lost. And Mr Trump has shown he is mortal. But what is the impact of this?

Well, the race for the Republican nomination has suddenly got a whole lot more interesting. The pathway that will get Mr Trump to the magic number of 1,237 delegates, the figure required to ensure a majority and thus a guarantee of the nomination, looks out of reach.

Yes, he will go into the convention with more delegates than Senator Ted Cruz, with many more votes than Ted Cruz, with very definitely the moral high ground for saying it should be him and nobody else.

But to coin a wonderfully old fashioned phrase once used by the British Prime Minister John Major, the moral high ground doesn't butter any parsnips. Donald's parsnips only get buttered by having a majority.

And without one the convention in Cleveland could become a free for all with any amount of jiggery-pokery going on. For political geeks it will be all their dreams and fantasies come true, for believers in the values of democracy it will be deeply challenging, and for Donald Trump it could mean something he is not used to tasting - defeat.

And if that happens his supporters would have every right to feel aggrieved and to feel cheated. It would be like saying: "Thank you for your millions of votes and your exercise of democracy these past six months, but we know what's best, and we'll take it from here..."

But before we all get too carried away, predictors of the imminent demise of Mr Trump have repeatedly got it wrong, and consistently over-estimated the gravity of the situation.