Imagine theres no Sgt Pepper. Its all too easy in the era of Trump and May | John Harris

This great Beatles album is as thrilling a listen as ever on its 50th anniversary: but its a melancholy time for the one-world counterculture the record soundtracked

At the time Sgt Pepper was released, the American writer Langdon Winner once recalled, I happened to be driving across the country on Interstate 80. In each city where I stopped for gas or food Laramie, Ogallala, Moline, South Bend the melodies wafted in from some far-off transistor radio or portable hi-fi For a brief while, the irreparably fragmented consciousness of the west was unified, at least in the minds of the young.

How far away it all seems. On 26 May the 50th anniversary of the Beatles Sgt Peppers Lonely Hearts Club Band (it actually falls on 1 June) will be marked by the release of remixed and repackaged versions of the original album. With his characteristically jolly humility, Paul McCartney insists in the latest issue of Mojo magazine that its just a record but its gained in notoriety over the years. The truth is that Sgt Pepper might be the most confident, boundary-pushing record British rock musicians have ever created, and it is worth revisiting again.

We might also think about the era the album crystallised, and its long legacy. Sgt Pepper is not quite the quintessentially psychedelic, love-and-peace artefact of historical cliche: streaked through its multicoloured dazzle is a very Beatle-ish kind of melancholy, partly rooted in the bands decidedly unpsychedelic postwar childhoods. But the wider cultural moment, and the Beatles place at its heart, were indeed replete with beads, bells and a wide-eyed optimism.

Three weeks after the album came out, the band were the biggest attraction in the worlds first global satellite TV show, singing All You Need Is Love to an audience of as many as 350 million. Meanwhile, on both the US west coast and in swinging London, young people on the cutting edge really were trying to push into a future very different from the one their parents had envisaged.

The so-called counterculture may not initially have reached much beyond its urban nerve centres and campuses. But the basic ideas Sgt Pepper soundtracked soon acquired enough influence to begin no end of social revolutions. A new emphasis on self-expression was manifested in the decisive arrival of feminism and gay liberation. Countries and borders came a distant second to the idea of one world.

Such shibboleths as marriage until death and a job for life were quickly weakened. Once the leftist unrest of 1968 was out of the way, the shift continued away from the old-fashioned politics of systems and social structures towards the idea of freeing ones mind everything coloured with an essentially optimistic view of the future.

Two years after Sgt Peppers release, a young graduate at Wellesley College, a women-only institution in Massachusetts, gave a speech. Our prevailing acquisitive and competitive corporate life, including tragically the universities, is not the way of life for us, she said. Were searching for more immediate, ecstatic, and penetrating modes of living. And so our questions, our questions about our institutions, about our colleges, about our churches, about our government continue.

Her name was Hillary Rodham, and her journey says a lot about where 1960s values eventually led us. To quote the music writer Charles Shaar Murray, the line from hippy to yuppie was not nearly as convoluted as some people subsequently liked to believe and once the love decades more ambitious alumni reached positions of power, the origin of many of their ideas was as clear as day.

Their professed distaste for corporate values fell away, but the hippy individualism summed up in the future Hillary Clintons insistence on immediate and ecstatic ways of life lived on, as did a questioning attitude to tradition, and to the stifling limitations of the old-fashioned nation state.

After the anti-60s backlash symbolised by Margaret Thatcher and Ronald Reagan, by the mid-90s such ideas were shaping a new political establishment, embodied by Bill Clinton, and Blair and Browns New Labour. I am a modern man, from the rocknroll generation. The Beatles, colour TV, thats my generation, said Blair. Clinton honked away at his saxophone and ended his rallies with a song by Fleetwood Mac.

It is not hard to read across from these politicians ideals to what they soaked up in their formative years. In 2005 Blair, who fronted a long-haired band while at Oxford University, told the Labour party conference that people should be swift to adapt, slow to complain open, willing and able to change. Collectivity was yesterdays thing; against a background of globalisation and all-enveloping liberalism, governments job was to encourage individuals to be as flexible and self-questioning as possible.