Washington: The TV anchorwoman was conducting a split-screen interview with a journalist who had volunteered to be a witness at the execution of a man on death row in Utah for 25 years. "He had a choice," said the journalist, "lethal injection or firing squad." "Wow!" said the anchorwoman. Cue a blizzard of commercials for fast food, tooth whitener, stomach stapling, the new Cadillac. This was followed by a reporter in Afghanistan sweating in a flak jacket. "Hey, it's hot," he said on the split screen. "Take care," said the anchorwoman. "Coming up" was a reality show in which the camera watched a man serving solitary confinement in a prison's "hell hole".

The next morning I arrived at the Pentagon for an interview with one of President Barack Obama's senior war-making officials. There was a long walk along shiny corridors hung with pictures of generals and admirals festooned in ribbons. The interview room was purpose-built. It was blue, ice cold, windowless and featureless except for a flag and two chairs: props to create the illusion of a place of authority. The last time I was in a similar room at the Pentagon, a colonel called Hum stopped my interview with another war-making official when I asked why so many innocent civilians were being killed in Iraq and Afghanistan. Then it was in the thousands; now it is more than a million. "Stop tape!" he had ordered.

Information warriors

This time there was no Colonel Hum, merely a polite dismissal of soldiers' testimony that it was a "common occurrence" that troops were ordered to "kill every motherfucker". The Pentagon, says the Associated Press, spent $4.7bn in 2009 alone on public relations: that is, winning the hearts and minds not of recalcitrant Afghan tribesmen, but of Americans. This is known as "information dominance" and PR people are "information warriors".

American imperial power flows through a media culture to which the word imperial is anathema. Colonial campaigns are really "wars of perception", wrote the present commander, General David Petraeus, in which the media popularise the terms and conditions. "Narrative" is the accredited word because it is postmodern and bereft of context and truth. The narrative of Iraq is that the war is won, and the narrative of Afghanistan is that it is a "good war". That neither is true is beside the point. They promote a "grand narrative" of a constant threat and the need for permanent war. "We are living in a world of cascading and intertwined threats," wrote the celebrated New York Times columnist Thomas Friedman, "that have the potential to turn our country upside down at any moment."

Friedman supports an attack on Iran, whose independence is intolerable. This is the psychopathic vanity of great power that Martin Luther King described as "the greatest purveyor of violence in the world". He was then shot dead.

The psychopathic is applauded across popular, corporate culture, from the TV death watch of a man choosing a firing squad over lethal injection to the Oscar-winning Hurt Locker and a new acclaimed war documentary, Restrepo. The directors of both films deny and dignify the violence of invasion as "apolitical". And yet, behind the cartoon façade is serious purpose. The US is engaged militarily in 75 countries. There are said to be as many as 900 US military bases across the world, many at the gateways to the sources of fossil fuels.

But there is a problem. Most Americans are opposed to these wars and to the billions of dollars spent on them. That their brainwashing so often fails is America's greatest virtue. This is frequently due to courageous mavericks, especially those who emerge from the centrifuge of power. In 1971, the military analyst Daniel Ellsberg leaked documents known as the Pentagon Papers, which put the lie to almost everything two presidents had claimed about Vietnam. Many of these insiders are not even renegades. I have a section in my address book filled with the names of former CIA officers who have spoken out. They have no equivalent in Britain.

Imperialism's face

In 1993, C Philip Liechty, the CIA's operations officer in Jakarta at the time of Indonesia's murderous invasion of East Timor, described to me how President Gerald Ford and Secretary of State Henry Kissinger had given the dictator Suharto a green light, secretly supplying the arms and logistics he needed. As the first reports of massacres landed on his desk, Liechty began to turn. "It was wrong," he said. "I felt badly."

Melvin Goodman is now a scholar at Johns Hopkins University in Washington. He was in the CIA for more than 40 years and rose to be a senior Soviet analyst. When we met the other day, he described the conduct of the cold war as a series of gross exaggerations of Soviet "aggressiveness" that wilfully ignored the intelligence that the Soviets were committed to avoid nuclear war at all costs. Declassified official files on both sides of the Atlantic support this view. "What mattered to the hardliners in Washington," Goodman said, "was how a perceived threat could be exploited." The present secretary of defence, Robert Gates, as deputy director of the CIA in the 1980s, was one of those who had hyped the "Soviet menace" and is, says Goodman, doing the same today "on Afghanistan, North Korea and Iran".

Little has changed. In America, in 1939, W H Auden wrote:

As the clever hopes expire
Of a low dishonest decade:
Waves of anger and fear
Circulate over the bright
And darkened lands of the earth,
Obsessing our private lives [. . .]
Out of the mirror they stare,
Imperialism's face
And the international wrong