Just shy of my sixth birthday when the Berlin Wall fell on 9 November 1989, I have no memory of ever being aware of the danger of imminent nuclear attack. For my oldest brother Seb, born in 1968, things were very different.

This difference in our childhoods has been highlighted by political events both here and across the Atlantic over the last few weeks. While Barack Obama continues to inspire with calls for a nuclear-free world, political realists in Washington, not least Obama's own defence secretary, Robert Gates, recognise that America may well be powerless to prevent the spread of nuclear weapons across the Middle East. Writing for the Boston Globe last week, the brilliant commentator HDS Greenway argued that even if America's military might were not already stretched thin, it would at best only be capable of delaying Iran's nuclear program for a few years. Meaning the necessary alternative for America is to learn to live with the Iranian bomb.

Back in the UK, the nation watched as Nick Clegg made the Lib Dems' case for reviewing the replacement of Trident – arguing for the need to look for a cheaper alternative or possibly, just possibly, even abandon an independent nuclear deterrent for Britain completely. It has been much commented upon that Clegg's proposal, toned down from earlier, bolder pronouncements on the subject, resulted in a rare moment of political agreement between David Cameron and Gordon Brown.

Debate will, of course, continue to rage over which politician and view is right. What I think is also worth looking at, however, is the reaction by different generations, both to the political issue of replacing Trident and to the global implications of continued nuclear armament.

Talking to Seb after the debate, I was struck by how angry he was. Angered by Brown and Cameron's reactions to Clegg – in particular, the fact both men expressed a belief that a nuclear deterrent makes us safer. But also infuriated that just one year after Obama's supremely optimistic speech in Prague, the idea of a nuclear-free world was being dismissed on both sides of the Atlantic as political naivety.

For someone who grew up during the cold war, the claim that a nuclear deterrent makes us feel safer, seems, to put it plainly, bollocks. After an afternoon watching archived Protect and Survive films I can begin to see why. These are chilling reminders of a different age, beginning with the image of a family silhouetted against a mushroom cloud and including lines such as: "A warning may come quite unexpectedly. Fall out can kill, though you cannot see it, feel it or smell it. There is danger outside."

Psychologist Professor Stanley Rachman, a leading authority on the development of anxiety, suggests "fears can be acquired by three pathways: conditioning, vicarious exposures and by the transmission of information and instruction". Just watching these dated public information films, let alone imagining the mood in the late 70s and early 80s, with the Doomsday Clock inching ever nearer midnight and emergency drills at school and home, there can be no doubt that the constant, terrible threat of nuclear holocaust fulfils all these criteria. Indeed, prompted by that fear, the activism of the CND was the driving force in politicising a generation.

For the generation that came after, this sensitised fear simply isn't there. Of course, we are aware and extremely concerned by both the danger and the mindboggling economic implications of a national nuclear arsenal. The anxiety over nuclear weapons, however, cannot help but be very different for anyone younger than 35, whose childhood was not lived under the ever-present, terrifying threat of the bomb. Our generation's political awakening was informed by the post-9/11 world. We marched against Iraq, but far fewer marched against nukes. Maybe because we simply weren't afraid.

What implications this shift in perspective may have, both for politicians seeking to engage with younger voters and also for those starting to take a role in deciding policy, is difficult to guess. A different frame of mind could prove perilous, leading us to underestimate the danger mutually assured destruction, or the lack of it, still poses. Or might it, instead, pave the way for a more rational approach to humanity's continued attempts to develop and maintain the ability to annihilate itself?