Last night in Florida, Hillary Clinton was fired up and angry. We haven't seen her this passionate on the campaign trail.

What provoked her was a protester, who shouted out that Bill Clinton was a rapist. Mrs Clinton replied furiously: "I am sick and tired of the negative, dark, divisive, dangerous visions and behaviors of people who support Donald Trump."

It was quite a moment, distilling in one sentence all the frustration building inside the candidate who thought victory was within her grasp.

In a sign of some desperation, the Clinton campaign is now deploying the biggest gun of them all. The President is in North Carolina today trying to recreate the winning coalition he first compiled eight years ago.

There is no secret to why he's been called for. The early signs - extrapolated from early voting data - is that African Americans are not turning up to the polls in the same numbers as four or eight years ago. It's the first empirical evidence that the Democrats may struggle with turnout among their normally reliable support groups.

But can President Obama turn the tide? In a few days we'll find out. Whatever happens, the political drama is only just beginning.

A wearily victorious Hillary Clinton would face paralysis by investigation. Republicans would launch endless probes and congressional inquiries. Tens of millions of Trump supporters will never deviate from their view she should be in prison, not the White House.

And if Donald Trump wins next week, America is going to face a political earthquake that will send tremors around the world. We will then have to entirely reassess our view of America, its values and its place in the world