World opinion has been unanimous about President Donald Trump’s decision to withdraw the United States from the Paris Accord on climate change.

Statements like these, expressing the effect of his decision, have been heard: America relinquishes its leadership of the world; US turns its back on the world; President Trump abdicates his global responsibility as leader of the free world, the decision will weaken America, and many more.

This is an image of America different from what we have been used to for a long time. The picture then was of a powerful but generous country, engaged and present everywhere in the world, and standing up for good and right.

Doubtless this was perhaps a little too romantic a view, helped in no small measure by American propaganda and projection of power. But it worked, certainly in parts of Africa. The uglier parts were successfully hidden and America’s goodwill grew.

Some of us grew up with this image of a generous United States. The first English words we learnt expressed this generosity.

They were emblazoned in big blue letters on sacks of yellow maize flour, tins of cooking oil and cartons of powdered milk: Donated by the People of the United States of America. It did not matter that we said them as if we were reading Kinyarwanda.

Below the words was a picture of a pair of hands in a firm handshake, not the Trump type, but presumably of friendship.

So here was a friendly nation extending a helping hand to people in need, like we were in refugee camps in countries neighbouring Rwanda.

The Europeans had learnt about this earlier, with the United States’ involvement in World War Two and the Marshall Plan for the reconstruction of Europe that followed.

The people who gave out relief supplies were a young and cheerful lot. In other parts of Africa, they were soon followed in nearly all the developing countries by another youthful army of Peace Corps who immediately immersed themselves into teaching, healthcare and community work with remarkable enthusiasm and energy.

Their boundless energy and optimism were a more effective advertisement of brand America than any number of diplomats could ever achieve.

Then the United States landed a man on the moon, not once, but several times. The Americans were not only good and generous; they were superhuman, gods even.

And so the power of America as a force for good and as an example of the limitless capacity for human achievement grew and spread. Hollywood did its bit, too, to advertise America and extend its influence.

Along the way the Americans preached democracy. It was an easy gospel to believe because of the example of its missionaries.

That was the rosy picture. There was an ugly one, too.

There was the war in Vietnam, supposedly fought to stem the advance of communism, a system that was portrayed as bad for humankind. The war turned ugly and brutal as untold atrocities were committed.

The little people from the rice paddies were proving more than a match for the military might of the United States.

Eventually America withdrew from Vietnam but with a huge dent in its power. Its aura of invincibility had been shattered. The good guy image had been tarnished and goodwill eroded.

At the height of the Vietnam war, the US was hit by its worst political scandal, Watergate. It exposed a huge moral deficit among the country’s highest political leaders. They were just as ruthless, unscrupulous and had a Macbeth-like appetite for power and the means to attain it as any dictator anywhere else in the world.

In Africa, the United States had a hand in the mess in the Congo and supported the apartheid regime in South Africa both at home and in its fight against nationalist forces in Namibia and Angola.

But even then, the attraction of the United States did not go away. Its leadership of the world remained and was bolstered by the collapse of the USSR and the coming down of the Berlin Wall.

A few other changes also helped. America withdrew from Vietnam. Apartheid was defeated in South Africa, and Namibia became free. Congo, well, it remains a mess.

It is different now. Donald Trump’s election as president of the United States and his actions since then, have accelerated the change.

To be fair, though, the change has been happening for a while. From the moment the US got involved in foreign wars again, the stock of goodwill has been diminishing. Finally, a withdrawal is happening, ironically at the same time as intervention in foreign conflicts is intensifying.

Withdrawal to narrow selfish interests has never been a satisfactory solution to global challenges. Events elsewhere have an impact even on those who choose isolation, and rather than create greatness this may actually lead to weakness.

Working towards the well-being of all of humanity is a more viable strategy. Remaining engaged is therefore a necessity.

It is possible to agree with Trump on his desire to make America great again, but as a strong and magnanimous nation, pursuing its national interest, not in isolation but in concert with the rest of the global community.

It is perhaps time to return to the diplomacy of reaching out that the handshake image of our childhood so ably symbolised.