I have been watching, over the past month, the superb series made under the aegis of that supreme documentarist, Ken Burns. It is the PBS series, ‘The West’.

It is a nine part series, most running for about an hour and 20 minutes each. In it the history of America’s westward expansion is chronicled, explored and described through the stories of many who lived, suffered and perished in what was an extraordinary mass movement of people across the land mass that we now know as the United States.

In the opening scenes a voice talks over the spectacular images of North America’s beautiful and sometimes terrifying landscapes. He tells us that the story we are about to hear is one which both makes the heart swell with pride and at the same time shrink in shame. It is an incredible story. But it is a story which – at one point in one of the nine episodes – we are reminded by former Texas governor, Ann Richards, follows the pattern of all conquests. It is replete with barbarism and injustice, with heroism and idealism – but above all, a kind of inevitability. Furthermore, it is a reminder of the fallibility of men, even of men who sincerely set for themselves the highest of ideals.

Everything in the story ‘The West’ tells us bears out and illustrates a reflective column by Michael Gerson in a recent edition of the Washington Post.

By definition, America can’t be a normal nation. It stands for more than getting and keeping. Its greatness is a greatness of spirit. And its failures — such as slavery, segregation and the shameful treatment of Native Americans — are not only legal but also spiritual failures. They are blasphemy against our country’s creed.

Does anyone think or talk like this now? They need to. There is so much dehumanization in our politics, and the main role of the Declaration is humanization. Its ideals are desperately needed and roundly ignored.

How do we measure our loss? It might be a useful exercise to take political arguments and apply the Declaration as a kind of suffix. So: We should fear Latino migrants as gang members and murderers . . . and all men and women are created equal. Or: Muslims are a threat and should be kept out of the country . . . and all men and women are created equal. Or: Spending on AIDS treatments for foreigners is a waste . . . and all men and women are created equal. Or: The human cost of a failing health or education system doesn’t matter . . . and all men and women are created equal. Or: Human beings can be dismembered up to the moment before birth . . . and all men and women are created equal.

Donal Trump rode to victory last year on the back of a slogan, ‘Make America Great Again’. Seeing ‘The West’ will make – or should make – every subscriber to that aspiration ask themselves about the cost that might be paid again if that greatness were to be pursued as ruthlessly and as incompetently as on the first path empire.