Do the sums, then compare US and Communist crimes from the Cold War

'There are no hard distinctions between what is real and what is unreal, nor between what is true and what is false. A thing is not necessarily either true or false; it can be both true and false."

No, that wasn't Secretary of State Condoleezza Rice, half-answering questions in Europe last week about the CIA's alleged prison camps in Poland and Romania and the "extraordinary rendition" of terrorist suspects to countries where they are likely to be tortured. It was actually Harold Pinter, explaining the difference between drama and politics in his acceptance speech for the Nobel Prize for Literature.

In the lofty realm of dramatic art, Pinter asserted, there can be nothing so clear-cut as truth. It is, however, a very different matter when it comes to American foreign policy. There, the distinction between true and false is as clear as that between day and night. It's simple. Every- thing the United States says is false, and everything its critics say is true.

Let me say right away that I am not about to mount a defence of the use of torture on suspected terrorists - though if anyone could provoke me into doing so, the insufferably vain Mr Pinter is the man. I do not care at all for Pinter's plays; if the Nobel committee wants to boost his bank balance and his ego, then that is their affair. God knows, the latter is big enough. Pinter's account of writing The Homecoming was surely worth a Nobel Prize for Pomposity: "It's a strange moment, the moment of creating characters who up to that moment have had no existence." Gee, almost like being God, Harold.

He also seemed to be angling for a Nobel Prize for Pathos: "A writer's life is a highly vulnerable, almost naked activity," he declared. "You are open to all the winds, some of them icy indeed. You are out on your own, out on a limb. You find no shelter, no protection." Aw, you're breaking my heart. But it's not Pinter's solipsism I really object to. It's the way he used his award to pour verbal kerosene on the crackling flames of anti-Americanism.

First, a few truths about torture. Torture is bad. It's bad because it's wrong to inflict pain on defenceless captives. It's bad because it breaks international conventions. And, even if you don't give a damn about either of those, it's bad because the costs outweigh the benefits of any intelligence it may elicit.

Reports that the CIA "waterboards" prisoners make a mockery of the Bush administration's repeated denunciations of Saddam Hussein as a torturer. They simultaneously increase the risk that any Americans or US allies who fall into the hands of al-Qaeda will themselves be tortured. And those reports are wrecking what little is left of the transatlantic alliance - witness Thursday's ruling by the Law Lords that evidence obtained from torture is inadmissible in British courts. The White House should shut up and back Senator John McCain's bill, which would unequivocally ban torture by American military or intelligence personnel.

The simple truth is that even if torture worked really well, the United States would still have to renounce it, because the CIA is so bad at keeping its dirty work secret. And precisely that point brings me back to Harold Pinter's rant.

Leave aside for today the invasion of Iraq, which he denounced in familiar terms. More intriguing was his extended critique of US policy - and secrecy - during the Cold War.

Here are Pinter's five charges:

1. The United States engaged in "low intensity conflict… throughout the world", causing "hundreds of thousands" of deaths. Pinter cites the case of Nicaragua, where American aid helped overthrow the "intelligent, rational and civilised" government of the Sandinistas.

2. "The United States supported and in many cases engendered every Right-wing military dictatorship in the world after the end of the Second World War", specifically those in Brazil, Chile, El Salvador, Guatemala, Greece, Haiti, Indonesia, Paraguay, the Philippines, Turkey and Uruguay. The deaths of all the people murdered by these regimes were "attributable to American foreign policy".

3. These "systematic, constant, vicious [and] remorseless" crimes bear comparison with those committed during the Cold War by the Soviet Union (no mention, be it noted, of China, Vietnam or North Korea).

4. But these crimes "have only been superficially recorded, let alone documented, let alone acknowledged". It is as if "it never happened", thanks to "a highly successful act of hypnosis".

5. This mass hypnosis has been achieved by repeated use of the phrase "the American people", which "suffocates [the] intelligence and… critical faculties" of all Americans - apart from "the 40 million people living below the poverty line and the 2 million men and women imprisoned in the vast gulag [sic] of prisons, which extends across the US".

Brings it all flooding back, doesn't it? The demand that the President and his allies be tried as "war criminals". The denunciation of the "infantile insanity" of nuclear weapons. No, don't worry, you haven't stepped into a time machine. It's not the 1970s, and that wasn't Henry Kissinger in drag, it was only Condi Rice. But yes, I am afraid that is still Harold Pinter, spouting the same old anti-American drivel he was spouting 30 years ago.

Truth and falsehood are indeed hard to distinguish in Pinter's drama, and his Nobel soliloquy was no exception. First, the true part. Thousands were indeed killed by US-backed dictatorships, especially in Central and South America. What is demonstrably false is that this violence is comparable in scale with that perpetrated by Communist regimes at the same time.

It is generally agreed that Guatemala was the worst of the US-backed regimes during the Cold War. When the civil war there was finally brought to an end in the 1990s, the total death toll may have been as high as 200,000. But not all these deaths can credibly be blamed on the United States. Most of the violence happened long after the 1954 coup, when the regime was far from being under the CIA's control.

By comparison, the lowest estimate for the number of people who were killed on political grounds in the last seven years of Stalin's life is five million, and the camps of the gulag - which only a fraud or a fool would liken to American prisons today - kept on killing long after his death. In their new biography, Jung Chang and Jon Halliday reckon Mao was responsible for anything up to 70 million deaths in China. The number of people killed or starved by the North Korean regime may be in the region of 1.6 million. The Khmer Rouge in Cambodia killed between 1.5 and 2 million people. For further details, I refer Pinter to The Black Book of Communism, published in 1997.

As for the allegation of a conspiracy to hush up American complicity in Cold War human rights violations, he really has to be kidding. You no longer need to rely on articles by Seymour Hersh to know about this stuff. There are easily accessible websites where you can download any number of declassified documents about all the dreaded dictatorships the CIA backed. On the basis of these and other sources, there have been at least five detailed monographs published in the last 10 years on Guatemala alone. Some cover-up.

Nobody pretends that the United States came through the Cold War with clean hands. But to pretend that its crimes were equivalent to those of its Communist opponents - and that they have been wilfully hushed up - is fatally to blur the distinction between truth and falsehood. That may be permissible on stage. I am afraid it is quite routine in diplomacy. But is unacceptable in serious historical discussion.

So stick to plays, Harold, and stop torturing history. Even if there was a Nobel Prize for it, you wouldn't stand a chance. Because in my profession, unlike yours - and unlike Condi's, too - there really are "hard distinctions… between what is true and what is false".

• Niall Ferguson is Laurence A. Tisch Professor of History at Harvard University