Last Night's Television - Sue Johnston's Shangri-La, BBC1; The Most Dangerous Man in America, BBC4

In the line of fire

We're hooked on the Winter Olympics coverage in our house. Where just a few days ago we talked about feeding the dogs and washing the dishes, now we talk about snowboard-cross, luge, and Nordic combined. So The Most Dangerous Man in America, showing in the Storyville strand, represented a rare sustained break from the action in Canada, but I was never going to let it pass without a nod to the ice and snow business, so here it is: the most satisfying thing about this brilliant documentary was seeing the momentum build in Richard Nixon's inexorable and spectacular slide downhill.

The emotive title refers to Daniel Ellsberg, a leading military strategist who in 1971, despairing of the futility of the Vietnam War and tormented by guilt over his own contribution, passed to The New York Times the top-secret 7,000-page report known as the Pentagon Papers, which revealed that the United States had gone to war on a series of false premises. Sounds familiar, doesn't it? Not least of the many reasons why this story made such captivating television was its resonance today, not that even George W Bush, Dick Cheney and Donald Rumsfeld can rank alongside Nixon for pure villainy.

Long before the end it was clear that the individual who really deserved to be called the most dangerous man in America was the jowly occupant of the Oval Office. Who else, after all, could make Henry Kissinger sound like a model of humanitarianism? We heard Kissinger advising Nixon against the use of nuclear warfare in Vietnam, to which an unimpressed Nixon growled: "I just want you to think big, Henry, for Chrissakes." Earlier, he urged the use of maximum US power "against this shit-ass little country to win the war". Kissinger, in the President's view, was far too principled. "You're so goddammed concerned about the civilians, and I don't give a damn."

All the best stories have a villain, but it is to the credit of Judith Ehrlich and Rick Goldsmith, who produced and directed this Oscar-nominated documentary, that they gave most of their attention to the hero of the piece. They were lucky, too, that so many of the protagonists are still alive and kicking. Kicking like mules, in fact, against the continuing myopia that afflicts US foreign policy. We saw Ellsberg and his splendid wife, Patricia, in San Francisco, leading a demonstration against the occupation of Iraq.

Although pushing 80, Ellsberg remains as impassioned and impressive a human being as he was 40 years ago. But the film delved deeper than politics, into the profoundly personal. Patricia talked lovingly of how she had been knocked sideways when she first set eyes on her future husband, a good-looking man even now, and strikingly handsome back then. More significantly, Ellsberg recalled a journey by road in 1946 when his father fell asleep at the wheel, crashing the car and killing his mother and sister. Ellsberg himself was left in a coma for 36 hours, and the revelation that his father, a decent man, could commit an error with such disastrous consequences, sowed the seeds for his later epic act of whistleblowing, which implicated not just the Nixon White House, but also the administrations of Truman (whom he admired), Eisenhower, Kennedy and Johnson.

In many ways, the documentary unfolded like a thriller. One by one, names cropped up in the story that we associate with another shameful passage in recent American history: among them, Mitchell, Ehrlichman, Dean and Howard Hunt. It gradually became clear that the Watergate scandal stemmed directly from Ellsberg's decision to leak the Pentagon Papers, because Nixon and his unscrupulous cohorts arranged for the office of Ellsberg's psychiatrist to be burgled, in the hope of finding information that would discredit him. It was the same team of burglars, the so-called White House plumbers, who would later commit the Watergate break-in, resulting in Nixon's eventual resignation.

Politics and unethical foreign policies were rather conspicuously absent from Sue Johnston's Shangri-La, in which the actress sallied forth from China to Tibet with nary a mention of brutal Chinese imperialism. Still, that wasn't exactly her brief. When Johnston was 15, her mother told her about Shangri-La, the mythical paradise described in James Hilton's novel Lost Horizon, and I can quite understand why, on Merseyside in the late 1950s, the concept of heaven on earth might have stirred the imagination.

Anyway, the BBC very obligingly put up the money and off she went to find the place that matched her mental image of Shangri-La, in the hope that it would help her find the peace of mind that has apparently proved troublingly elusive in her life. I've met Johnston a few times and she's a lovely woman, so I was happy to go along with this, although I suppose less sympathetic viewers might have tired of her somewhat plaintive introspection. These travelogues don't always have to be exercises in Paul Merton-style jauntiness, though, and I was delighted when Johnston found her mountain-top. If only she'd set off down it on a luge, my evening would have been complete.