I’ll admit my love affair with America has been a tangled business. It is layered with both love and hate. It is laced with romance, myth, endless misbehaviour, violence, and tragedy.

It affects us all, this complex “leader of the free world”. Ultimately it is an eternal and unhappy affair, and yet I cannot leave it.

I lived in America as a correspondent at the very zenith of American power in the build-up to the moment when the 20th century’s “60-year war” – the cold war – was “won”.

I shall never live so well again. In my pillared white wooden home, with its deck, on the tree-lined Macomb Street in Washington’s Cathedral district. The sky was blue, the seasons moved between freeze and sweat across the four years that I lived there.

The horrific massacre of the innocents and their mentors in Newtown, Connecticut have brought it all back. What is it about America that renders so powerful a nation so incapable of coping with its once brilliant constitution?

On the day of the shooting, before it happened, in a Twentieth Century Fox viewing theatre in London’s Soho, I watched Lincoln, Stephen Spielberg’s completely brilliant and devastatingly moving film centred around the greatest American president who ever lived.

More from Channel 4 News on the Connecticut shootings

Even today, I cannot think that Lincoln – who ended the civil war, ended slavery; and saved the American Union – would not have won the debate on guns.

Spielberg’s remarkable film draws from a portion of the book Lincoln Team of Rivals by Doris Kearns Goodwin. I have said before that I regard this book, which Obama took with him into the White House, as one of the most exceptional books written in our time.

Thus far, President Obama has not attained the heights that Lincoln achieved. Although, heaven knows he has been inflicted with a Congress at least as cantankerous as the one Lincoln suffered. But after Newtown, assaulting gun control will now be seen as a key challenge if Obama is to nudge the reputation of his presidential hero.

But there are so many other challenges in his political shunting yard. There’s the matter of health care – seen by many of us beyond America’s shores as a fundamental human right that we almost (dangerously?) take for granted. Then there is “the abroad”. Iran, Syria, the world economy, China, and so much more.

Who would be Obama? Many argue that America has peaked. Some will see Newtown as the horrific failure of one structural element of the dream of “freedom” that Lincoln dreamt.

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