A conversation with Gore Vidal unfolds at his pace. He answers questions imperiously, occasionally playfully, with a piercing, lethal dryness. He is 83 and in a wheelchair (a result of hypothermia suffered in the war, his left knee is made of titanium). But he can walk (“Of course I can”) and after a recent performance of Mother Courage at London’s National Theatre he stood to deliver an anti-war speech to the audience.

How was his friend Fiona Shaw in the title role? “Very good.” Where did they meet? Silence. The US? “Well, it wasn’t Russia.” What’s he writing at the moment? “It’s a little boring to talk about. Most writers seem to do little else but talk about themselves and their work, in majestic terms.” He means self-glorifying? “You’ve stumbled on the phrase,” he says, regally enough. “Continue to use it.”

Vidal is sitting in the Connaught Hotel in Mayfair, where he has been coming to stay for 60 years. He is wearing a brown suit jacket, brown jumper, tracksuit bottoms; his white hair twirled into a Tintin-esque quiff and with his hooded eyes, delicate yet craggy features and arch expression, he looks like Quentin Crisp, but accessorised with a low, lugubrious growl rather than camp lisp.

He points to an apartment opposite the hotel where Churchill stayed during the Second World War, as Downing Street was “getting hammered by the Nazis. The crowds would cheer him from the street, he knew great PR.” In a flash, this memory reminds you of the swathe of history Vidal has experienced with great intimacy: he was friends with JFK, fought in the war, his father Gene, an Olympic decathlete and aeronautics teacher, founded TWA among other airlines and had a relationship with Amelia Earhart. (Vidal first flew and landed a plane when he was 10.) He was a screenwriter for MGM in the dying days of the studio system, toyed with being a politician, he has written 24 novels and is hailed as one of the world’s greatest essayists.

He has crossed every boundary, I say. “Crashed many barriers,” he corrects me.

Last year he famously switched allegiance from Hillary Clinton to Barack Obama during the Democratic nomination process for president. Now, he reveals, he regrets his change of heart. How’s Obama doing? “Dreadfully. I was hopeful. He was the most intelligent person we’ve had in that position for a long time. But he’s inexperienced. He has a total inability to understand military matters. He’s acting as if Afghanistan is the magic talisman: solve that and you solve terrorism.” America should leave Afghanistan, he says. “We’ve failed in every other aspect of our effort of conquering the Middle East or whatever you want to call it.” The “War on Terror” was “made up”, Vidal says. “The whole thing was PR, just like ‘weapons of mass destruction’. It has wrecked the airline business, which my father founded in the 1930s. He’d be cutting his wrists. Now when you fly you’re both scared to death and bored to death, a most disagreeable combination.”

His voice strengthens. “One thing I have hated all my life are LIARS [he says that with bristling anger] and I live in a nation of them. It was not always the case. I don’t demand honour, that can be lies too. I don’t say there was a golden age, but there was an age of general intelligence. We had a watchdog, the media.” The media is too supine? “Would that it was. They’re busy preparing us for an Iranian war.” He retains some optimism about Obama “because he doesn’t lie. We know the fool from Arizona [as he calls John McCain] is a liar. We never got the real story of how McCain crashed his plane [in 1967 near Hanoi, North Vietnam] and was held captive.”

Vidal originally became pro-Obama because he grew up in “a black city” (meaning Washington), as well as being impressed by Obama’s intelligence. “But he believes the generals. Even Bush knew the way to win a general was to give him another star. Obama believes the Republican Party is a party when in fact it’s a mindset, like Hitler Youth, based on hatred — religious hatred, racial hatred. When you foreigners hear the word ‘conservative’ you think of kindly old men hunting foxes. They’re not, they’re fascists.”

Another notable Obama mis-step has been on healthcare reform. “He f***ed it up. I don’t know how because the country wanted it. We’ll never see it happen.” As for his wider vision: “Maybe he doesn’t have one, not to imply he is a fraud. He loves quoting Lincoln and there’s a great Lincoln quote from a letter he wrote to one of his generals in the South after the Civil War. ‘I am President of the United States. I have full overall power and never forget it, because I will exercise it’. That’s what Obama needs — a bit of Lincoln’s chill.” Has he met Obama? “No,” he says quietly, “I’ve had my time with presidents.” Vidal raises his fingers to signify a gun and mutters: “Bang bang.” He is referring to the possibility of Obama being assassinated. “Just a mysterious lone gunman lurking in the shadows of the capital,” he says in a wry, dreamy way.

Vidal now believes, as he did originally, Clinton would be the better president. “Hillary knows more about the world and what to do with the generals. History has proven when the girls get involved, they’re good at it. Elizabeth I knew Raleigh would be a good man to give a ship to.”The Republicans will win the next election, Vidal believes; though for him there is little difference between the parties. “Remember the coup d’etat of 2000 when the Supreme Court fixed the selection, not election, of the stupidest man in the country, Mr Bush.”

Vidal says forcefully that he wished he’d never moved back to the US to live in Hollywood, from his clifftop home in Ravello, Italy, in 2000. His partner of 53 years, Howard Austen, who died in 2003, collated a lifetime’s-span of pictures of Vidal, for a new book out this autumn, Gore Vidal: Snapshots in History’s Glare (an oddly clunky title). The cover shows what a beautiful young man Vidal was, although his stare is as hawkish as it is today.

He observes presidential office-holders balefully. “The only one I knew well was Kennedy, but he didn’t impress me as a good president. It’s like asking, ‘What do I think of my brother?’ It’s complicated. I’d known him all my life and I liked him to the end, but he wrecked his chances with the Bay of Pigs and Suez crises, and because everyone was so keen to elect Bobby once Jack had gone, lies started to be told about him — that he was the greatest and the King of Camelot.”

Today religious mania has infected the political bloodstream and America has become corrosively isolationist, he says. “Ask an American what they know about Sweden and they’d say ‘They live well but they’re all alcoholics’. In fact a Scandinavian system could have benefited us many times over.” Instead, America has “no intellectual class” and is “rotting away at a funereal pace. We’ll have a military dictatorship fairly soon, on the basis that nobody else can hold everything together. Obama would have been better off focusing on educating the American people. His problem is being over-educated. He doesn’t realise how dim-witted and ignorant his audience is. Benjamin Franklin said that the system would fail because of the corruption of the people and that happened under Bush.”

Vidal adds menacingly: “Don’t ever make the mistake with people like me thinking we are looking for heroes. There aren’t any and if there were, they would be killed immediately. I’m never surprised by bad behaviour. I expect it.”

While materially comfortable, Vidal’s was not a happy childhood. Of his actress and socialite mother Nina, he says: “Give her a glass of vodka and she was as tame as could be. Growing up is going to be difficult if the one person you hate is your mother. I felt trapped. I was close to my grandparents and my father was a saint.” His parents’ many remarriages means that even today he hasn’t met all his step-siblings.

He wrote his first novel, Williwaw, at 19. In 1948, he was blacklisted by the media after writing The City and the Pillar, one of the earliest novels to deal graphically with homosexual desire. “You’ll be amazed to know it is still going strong,” he says. The “JT” it is dedicated to is James “Jimmy” Trimble, Vidal’s first love and, he once said, the love of his life. “That was a slight exaggeration. I said it because there wasn’t any other. In the new book there are wonderful pictures of him from our schooldays. He was a great athlete.” Here his voice softens, and he looks emotional, briefly. “We were both abandoned in our dormitory at St Alban’s [boarding school]. He was killed at the Battle of Iwo Jima [in 1945] because of bad G2 [intelligence].”

Vidal says Trimble’s death didn’t affect him. “No, I was in danger of dying too. A dead man can’t grieve a dead man.” Has love been important to him? “Don’t make the error that schoolteacher idiots make by thinking that gay men’s relationships are like heterosexual ones. They’re not.” He “wouldn’t begin to comment” on how they are different.

In 1956 he was hired by MGM, collaborated on the screenplay for Ben Hur and continued to write novels, most notoriously Myra Breckenridge about a transsexual. It is his satires, essays and memoirs — Live From Golgotha, Palimpsest and most recently, Point to Point Navigation — which have fully rounded our vision of this thorny contrarian, whose originality springs simply, and naturally, from having deliberately unfixed allegiances and an enduring belief in an American republic and railing sadness at how that ideal has been corrupted.

Vidal became a supportive correspondent of Timothy McVeigh, who blew up the Alfred P. Murrah Building in Oklahoma City in 1995 killing 168 people. The huge loss of life, indeed McVeigh’s act of mass murder, goes unmentioned by Vidal. “He was a true patriot, a Constitution man,” Vidal claims. “And I was torn, my grandfather [the Democrat Senator Thomas Gore] had bought Oklahoma into the Union.” McVeigh claimed he had done it as a protest against tyrannical government. The writer Edmund White took the correspondence as the basis for a play, Terre Haute (the jail McVeigh was incarcerated in before he was executed in 2001), imagining an encounter between the bomber and Vidal charged with desire.

“He’s a filthy, low writer,” Vidal says of White. “He likes to attack his betters, which means he has a big field to go after.” Had he wanted to meet McVeigh? “I am not in the business of meeting people,” Vidal says. “That play implies I am madly in love with McVeigh. I looked at his [White’s] writing and all he writes about is being a fag and how it’s the greatest thing on Earth. He thinks I’m another queen and I’m not. I’m more interested in the Constitution and McVeigh than the loving tryst he saw. It was vulgar fag-ism.”

Vidal says that he hates labels and has said he believes in homosexual acts rather than homosexual people. He claims his relationship with Austen was platonic (though they reputedly met at a legendary New York bath-house). He was once quoted as saying that he’d had sex with a 1,000 men by the time he was 25. It must have been a little strange for Austen, Vidal’s life companion, to source those pictures of Trimble, his first, perhaps only, love.

Vidal puts on a scornful, campy voice. “People ask [of he and Austen], ‘How did you live together so long?’ The only rule was no sex. They can’t believe that. That was when I realised I was dealing with a public too stupid by half. They can’t tell the difference between ‘The Sun rose in the East’ and ‘The Sun is made of yeast’.” Was sex important to Vidal? “It must have been yes.”

He is single now. “I’m not into partnerships,” he says dismissively. I don’t even know what it means.” He “couldn’t care less” about gay marriage. “Does anyone care what Americans think? They’re the worst-educated people in the First World. They don’t have any thoughts, they have emotional responses, which good advertisers know how to provoke.” You could have been the first gay president, I say. “No, I would have married and had nine children,” he replies quickly and seriously. “I don’t believe in these exclusive terms.”

Impaired mobility doesn’t bother him — he “rose like a miracle” on stage at the National — and he doesn’t dwell on mortality either. “Either you accept there is such a thing or you’re so dumb that you can’t grasp it.” Is he in good health? “No, of course not. I’m diabetic. It’s odd, I’ve never been fat and I don’t like candy, which most Americans are hooked on.”

There is a trace of thwarted ambition about him. “I would have liked to have been president, but I never had the money. I was a friend of the throne. The only time I envied Jack was when Joe [Kennedy, JFK’s father] was buying him his Senate seat, then the presidency. He didn’t know how lucky he was. Here’s a story I’ve never told. In 1960, after he had spent so much on the presidential campaign, Joe took all nine children to Palm Beach to lecture them. He was really angry. He said, ‘All you read about the Kennedy fortune is untrue. It’s non-existent. We’ve spent so much getting Jack elected and not one of you is living within your income’. They all sat there, shame-faced. Jack was whistling. He used to tap his teeth: they were big teeth, like a xylophone. Joe turned to Jack and he says, ‘Mr President, what’s the solution?’ Jack said, ‘The solution is simple. You all gotta work harder’.” Vidal guffaws heartily.

Hollywood living proved less fun. “If there was a social whirl, you can be sure I would not be part of it.” He does a fabulous impression of Katharine Hepburn complaining about playing the matriarch in Suddenly Last Summer, which he wrote. “I hate this script,” he recalls Hepburn saying . “I’m far too healthy a person to know people like this.” Vidal snorts. “She had Parkinson’s. She shook like a leper in the wind.”

I ask what he wants to do next. “My usual answer to ‘What am I proudest of?’ is my novels, but really I am most proud that, despite enormous temptation, I have never killed anybody and you don’t know how tempted I have been.”

That wasn’t my question, I say. “Well, given that I’m proudest that I haven’t killed anybody, I might be saving something up for someone.” A perfect line: we both laugh.”—–NOW TELL ME IF THAT MAN(ELIJAH MUHAMMAD IS ON TIME!!!

Is he happy? “What a question,” he sighs and then smiles mischievously. “I’ll respond with a quote from Aeschylus: ‘Call no man happy till he is dead’.”