Floyd's horrific ordeal was recorded on video along with the police unmoved by his anguished cries to breathe or by the pleas from witnesses to desist - events so shocking that they have led the news here, half a world away.

President Trump is not one to resile from shows of police force. In a speech to police in 2017, he said:

"When you guys put somebody in the car and you're protecting their head, you know, the way you put their hand over? Like, don't hit their head, and they just killed somebody - don't hit their head," Trump continued. "I said, you can take the hand away, okay?"

But Trump got what happened to George Floyd: "That's a very shocking sight. I saw it last night and I didn't like it ... a very very bad thing that I saw."

The murder of Mr Floyd follows the killing, also captured on video of the killing of Ahmaud Arbery, the jogger in Georgia.

Indeed, without these videos, would those who killed these men be facing justice?

That's one spark to what we are seeing in America today. In nearly two dozen American cities, there are riots, curfews and troops called in to restore order.

Trump was quite daunted by what he saw outside the White House on Friday night. As The Washington Post reported: "More than 1,000 demonstrators massed along Pennsylvania Avenue, throwing bricks and rocks and dispersing only after 3am, when the Secret Service began to fire chemical agents. No similar scene has unfolded within view of the North Portico of the president's home in recent memory."

I was born in Washington DC and have seen the capital endure wrenching times. When Martin Luther King Jr was assassinated in April 1968, large parts of Washington burned. Troops were stationed in our neighbourhood in the northwest part of the city; days and nights of mourning and fear and hopelessness.

During the Vietnam War, when protesters would target President Nixon, buses would be driven and parked boot-to-bonnet at the White House perimeter, preventing the demonstrators from breaching the White House grounds.

During the first Gulf War, troops with machine guns patrolled the North Lawn of the White House to protect President George H.W. Bush, evoking a mood in the capital last felt in WWII.

The country today is deeply riven by forces of a profound stress, more than at any time since the civil rights movement, together with the tragedy of the Vietnam War, divided the country in the 1960s and 70s.

This last week has been just terrible.

The death toll of 100,000 lost from COVID-19 was crossed: the number of lives lost on September 11 repeated every three days over 90 days. While post-peak in many states, such as New York, it is still accelerating in others, and thousands more will die in the coming weeks. A second wave may yet hit before the year is out, and while extraordinary, unprecedented work is being done to secure a vaccine, that is far from assured.

Unemployment has soared with 40 million out of a job in a tanking economy, with no prospects for a quick improvement as America re-opens.

And now violence is erupting from coast to coast.

In times of profound crisis, Americans turn to their president for comfort and direction. Think of Ronald Reagan after the Challenger spacecraft was lost on take-off, Bill Clinton after the bombing of the government building in Oklahoma City, George W. Bush in the rubble of the twin towers days after September 11, Barack Obama after the massacre of school kids in Connecticut (it was his hardest day as president, he has said), and singing Amazing Grace after black parishioners were murdered in a church in South Carolina.

But Trump does not do empathy. The United States has a president who is unable or unwilling to help bring the country together.

Trump did indeed, after yesterday's successful SpaceX launch in Florida, open up for the first time with words of healing. "Yesterday I spoke to George's family and expressed the sorrow of our entire nation for their loss. I stand before you as a friend and ally to every American seeking justice and peace ... Healing, not hatred, justice, not chaos, are the mission at hand."

But before those remarks, he tweeted from Air Force One: "Crossing State lines to incite violence is a FEDERAL CRIME! Liberal Governors and Mayors must get MUCH tougher or the Federal Government will step in and do what has to be done, and that includes using the unlimited power of our Military and many arrests. Thank you!"

And afterwards, he tweeted this: "The National Guard has been released in Minneapolis to do the job that the Democrat Mayor couldn't do. Should have been used 2 days ago & there would not have been damage & Police Headquarters would not have been taken over & ruined. Great job by the National Guard. No games!"

These are the worst of times in today's America. What is unfolding is what will frame the choice to be made by the American people in November. We will hear more on "law and order" from Trump. From Joe Biden, we will hear more about binding up the nation's wounds. And the American people will choose their future in the hope of coming back from these terrible times for the country.