Well before we could see the presidential motorcade, we could hear its progress. As it cruised down Oxford Street, a cascade of cheers from the multitudes packed onto the footpaths streamed down the lines. The papers later reported a million people had turned out in Sydney on Saturday 22 October 1966 – 50 years ago today – to welcome the American president.

Then we spotted it, the motorcade turning at a stately pace into Liverpool Street, a dozen black limos gleaming, the president and First Lady in a Lincoln Continental with twinned American and Australian flags fluttering on its bonnet. A squad of police motorcycle outriders and a press bus led the way. The antiwar protesters, a few hundred strong and most of them students and activists like me, were waiting further down, opposite Hyde Park, and as the cavalcade approached, the booing began and the stop-the-war placards shot up. A dozen or so of us readied ourselves for a more direct action.

The official slogan coined for this 1966 visit to Sydney of US President Lyndon Baines Johnson was, incredibly, ‘Make Sydney Gay for LBJ’. It was the first-ever visit by an American president to the devoted ally down under and officialdom was bending over backwards to accommodate the head of state gracing us with his presence, even if it was only a stopover on the way to a conference in Manila of America’s Asian allies in the war in Vietnam.

We were part of the anti-Vietnam War movement and we were angry. For more than a year LBJ had been escalating the war in Vietnam. US planes were bombing large swathes of Vietnam back to the Stone Age (to use a phrase attributed to US air force chief Curtis LeMay). Hundreds of thousands of American troops were battling peasant guerrillas in the paddy fields and jungles of Vietnam and villages were being napalmed.

Johnson, three years into his presidency after Kennedy’s assassination, was at the centre of this carnage. His sympathetic and Pulitzer Prize-winning biographer Robert A Caro has acknowledged the casualties and the blood on Johnson’s hands:

It may be [that] more than two million men and women and children [were] killed and maimed and burned alive, some by bombs dropped on villages selected as targets by Johnson himself, dropped by B-52s which flew so high that they were not only invisible but unheard from the ground, so that the people in the villages did not know they were in danger until the bombs hit.

So if the protesters who lay in wait for the president in Australia had a slogan, it was ‘Hey! Hey! LBJ! How many kids have you killed today?’ But in 1966 those dissidents were still a small minority. It was only 25 years since Australia had turned to the United States to defeat the mortal threat from Japan. Most Australians were viscerally pro-American – and still fearful of Asia. Even after the defeat of Japan, other threats from the north – China and communist-led peasant revolutions – were conjured up by conservative politicians and mainstream media commentators.

No surprises, then, that when President Johnson landed in the national capital on Thursday 20 October 1966, tens of thousands of Canberrans welcomed him. Or that an estimated half a million Melburnians lined the streets of their city to hail the chief on Friday. There were protests in those cities but they were largely contained, footnotes in the media coverage.

Sydney was planned to be the climax of the visit. The state government decreed free travel for school kids from all over the state. A thousand children in ten-gallon hats (LBJ was a Texan) were organised to welcome the president at the airport. Anzac Parade was renamed ‘President Johnson Way’. Badges with the president’s face and crossed flags were given away en masse. Free flags and streamers printed with the slogan ‘Hip Hip Hooray for LBJ’ were issued to the crowds along the route from Mascot to the Art Gallery where the president was to lunch with 1200 of Sydney’s worthiest citizens. In the end, the trip from airport to the gallery would take much less time than officials had anticipated.

Filmmaker Kit Guyatt was one of the dozen in on the plan. He was 19, an anarchist, and, an advantage in this circumstance, small. ‘It meant I could slip between the legs of one of the police holding back the crowd. No sooner had I slipped through than the line broke as the police turned to catch me.’

As the thin blue line opened up, the rest of us saw our opportunity. We ducked under the barriers and sat down in the middle of the road. (Press reports later described us as ‘girls and bearded men’, although at least one of us was not only clean-shaven but was dressed in a natty suit and tie.)

The crowd’s chanting of ‘Stop the War’ throttled up. The motorcade stopped dead. The NSW Premier Sir Robin Askin, riding with LBJ and the First Lady (Ladybird Johnson), put his head out the car window to find out what the trouble was. Seeing a tangle of protesters lying down in the presidential pathway he lost it, yelling ‘drive over the bastards’ to the cars in front.

Momentarily the coppers were stunned. Then, led by the police commissioner Norm Allan himself – he’d jumped out of the lead car in the motorcade when it stopped – the scattered police began to drag us off the road. Jean Curthoys, now a retired academic but then a rebellious 18-year-old from a well-known communist party family, recalls determinedly pitching herself onto the road three or four times. ‘Police picked me up and dumped by the side of the road, so I just jumped up and ran back.’

I took my place in the middle of the road next to my ALP comrade Aiden Foy but I wasn’t there for long. Seeing the stationary press bus 10 metres away, I made a dash for it. I’d like to say it was a reasoned move because I was editor of honi soit, the student newspaper at Sydney Uni, but in truth, it was just an impulse to jump on board. Fronting a bus full of what appeared to be startled American reporters – judging by their crew-cuts, sports jackets and the button-downed collars of their striped shirts – I announced the bleeding obvious, that this was an antiwar protest. The longer speech I would have liked to deliver to this captive audience was cut short as the bus began to move. I threw in a couple of chants and jumped off.

The road had been cleared and the motorcade sped away, now racing through the city in case of more unexpected incidents.

As the Sun Herald reported: ‘After a sharp clash in Oxford Street, secret service men ordered the motorcade to clap on speed and it rushed through the city at breakneck speed to the state reception at the Art Gallery. As a result, hundreds of thousands of people caught only a fleeting glimpse of the president … People stood bewildered as the motorcade flashed by and children burst into tears because they had missed their chance to wave to the president.’

In the panic, the two scheduled stops in the city were dispensed with – including Queen’s Square where a group of pigeon fanciers waited to release 200 racing pigeons, as stand-ins apparently for doves of peace.

The sitdown itself was over in a couple of minutes. But the newspaper photographers had caught it and it was the sitdown rather than the cheering Sydneysiders that made the headlines. WILD BRAWLS IN LBJ WELCOME was the Daily Mirror’s banner headline, while The Sun trumpeted: BRAWLS, RIOT AND A BOMB SCARE. Overseas, it made the New York Times and other newspapers across the United States.

A handful of anti-Vietnam War activists had upstaged what they saw as a latter-day Billy Graham rally on wheels. Monday’s Sydney Morning Herald was not pleased, editorialising:

The point is not that the demonstrators won a victory – as they undoubtedly did … it is that they were allowed to win it. Those who deserve to have the vials of wrath emptied on them are those in charge of security arrangements.

The police commissioner agreed, firing off a please-explain memo to Special Branch, whose duty it was to spy on communists and other trouble-makers and foil their plans. From now released files we know that our secret police – ASIO as well as Special Branch – were in fact aware that something like the sitdown was being plotted. (We also know from the same files it was the police commissioner’s bright idea to position the Mormon choir and PA next to the antiwar protesters.)

Trouble was, they were looking in all the wrong places for the conspirators. The three main protest organisers in Sydney at that time were Bob Gould’s Vietnam Action Campaign, the Communist Party, and the Youth Campaign Against Conscription (basically run by young ALP left-wingers Barry Robinson and Wayne Haylen). The three group’s were locked in an uneasy alliance, two parts cooperation, one part mutual suspicion.

Prior to the visit, ASIO’s phone taps and informants established that the Communist Party was planning a strictly peaceful protest to greet LBJ, although the communists were worried about being upstaged by Bob Gould, a Trotskyist activist who had almost singlehandedly launched the antiwar movement in Australia.

The records of the phone intercepts reveal that Robinson and Haylen were equally worried about Bob going over the top. They feared a backlash to Labor’s electoral prospects in the looming November federal election from any ultra-left incident involving antiwar protesters.

The telephonic chatter recorded in ASIO files establishes that Bob Gould was interested in some kind of sitdown in front of the motorcade but his idea was that it should be distant from the massed antiwar protesters in Liverpool Street, where the police presence would be heaviest. Meanwhile, those of us from the Sydney University Left were also planning a sitdown but hadn’t told Bob Gould about it, precisely because it was our best chance of remaining undetected, knowing that Gould’s phone was very likely tapped.

Unintentionally, Gould’s overheard plans for a sitdown elsewhere served as a decoy. On the day the police were looking elsewhere rather than in plain sight at the main demo itself.

The real plotters behind the sitdown were only revealed weeks later when the Commonwealth Police named me as the chief culprit. In their version, I had ‘apparently’ convened the meeting at the University of Sydney of radical students and the Sydney Libertarians which had planned the sitdown. The crucial meeting in fact had taken place in a downtown pub, which was logical enough as the Sydney Libertarians were a group of anarchist punters who met regularly in pubs and were in the process of turning their attention from the races at Randwick to the war in Vietnam.

In retrospect, it was amazing that we were able to carry out the plan. The presidential visit was three years almost to the day since the assassination of President Kennedy yet by modern day standards security was extraordinarily slack. In Melbourne, which had its motorcade the day before Sydney, two paint bombs or balloons filled with red and blue paint – the colours in the flag of the National Liberation Front of South Vietnam, the Vietcong – landed on the presidential limousine in Swanston Street.

The car was rushed off to Ford’s Geelong plant where it was given a quick respray in time for it to be shipped to Sydney. Incredibly, it was the very same car John F Kennedy was riding in when he was shot in in Dallas. It had since been enclosed with a clear bubble top.

The president, it was reported, brushed aside our sitdown as the ‘antics’ of a small minority. Meanwhile, the press lavishly reported his speeches in which he boasted that the North Vietnamese would never win the war and proclaimed the ‘light at the end of the tunnel’ in the Americans’ quest for victory. Fifteen months later, all that optimism turned to mush with the NLF’s Tet Offensive, when the supposedly defeated peasant guerrillas stormed into every town and city in South Vietnam. Soon after Tet, faced with passionate campus and ghetto rebellions at home, and even defeat in his party’s primaries for the nomination, a broken LBJ announced he would not be standing in the presidential elections of 1968.

Compared to the firestorm of protests that overwhelmed LBJ at home, that early Sydney sitdown was only a pinprick. Yet it was the first sign that this American president, elected in a landslide just two years before and welcomed by many Australians as a demi-god, was far from impregnable. In retrospect I am astonished at our audacity in daring to sit down in front of the motorcade, in ‘disrespecting’ the great United States president. In a small way, however, we were part of an historical turning point. As the distinguished American journalist of the time, Tom Wicker, has written, ‘it is difficult to remember, much less to understand, the extent to which “the President”, any President, was revered, respected’ before Lyndon Baines Johnson. The protesters had played their part in the shattering of that aura.