On the wall by my desk, there's a spread of photos of Aung San Suu Kyi which appeared in the Guardian a year ago. It's a kind of family photo album with snaps of engagement, babies, university, chilly British family picnics and travels. It's a strikingly poignant illustration of everything Aung San Suu Kyi has sacrificed over 15 years of imprisonment in her struggle for Burmese democracy. Every time it catches my eye, it is both humbling and gives me hope: a reminder of what the human spirit is capable of.

Illustration by Andrzej Krauze

Much has been made of her remarkable biography – catapulted by circumstance from family life in Oxford into the violent repressive politics of Burma in 1988; missing the illness and death of her husband and the raising of her children to pursue the cause. What makes her Reith lectures so fascinating is they represent a statement of the ideals and mindset which have steeled her resolve and inspired her courage. The first lecture addresses the universal human desire for freedom, the second considers her fight in Burma to achieve it. She is taking her stand on an ideal to which the west has a tendency to claim copyright in the Enlightenment. What's more, freedom is an ideal which has been bastardised in recent years by the rhetoric of two disastrous American wars. Deftly, she lays out an understanding of freedom which owes more to Buddhism than western philosophy and, in so doing, injects a radical new meaning into an abused ideal. She is simultaneously quietly challenging western hubris and offering her global audience a new interpretation.

She does this not by expounding on obscure Buddhist philosophy – there is only one explicit mention of Buddhism – but by translating her spiritual tradition into a wide range of western thinkers, poets and writers: Vaclav Havel, the Russian poet Anna Akhmatova, Ratushinskaya, Henley, Kipling and Isaiah Berlin. What is far more important to her than a sales pitch for a much misunderstood religion/philosophy is that her global audience connect to what she is saying and she helps by giving plenty of familiar reference points, slipping the unfamiliar in alongside. She weaves in Christian metaphors and concepts with the Buddhism, Russian poetry and the eastern European dissident tradition. It is a unique synthesis of east and west, only possible in someone deeply versed in both.

Many of her western admirers will immediately grasp the language of human rights. It is the Buddhism which may be less comprehensible; for instance she recounts an anecdote in which people ask how it felt to be free after each period of house arrest, to which she replied "my mind had always been free". Or, in another passage, she says "Buddhism teaches that the ultimate liberation is liberation from all desire". Perhaps these are the points where western minds shift uncomfortably at the proximity of spiritual faith to politics. But the most crucial fact about Aung San Suu Kyi's politics is how it is rooted in her Buddhism.

For her, freedom is not only a set of institutions, laws and political processes, it is also a quest of the individual spirit, the struggle to free oneself from greed, fear and hatred and how they drive one's own behaviour. That is why she always talks of a "revolution of the spirit". You cannot have one without the other, both are part of transformational change; the individual and personal is inextricably bound up with the political, as she made clear in her interviews with the American Buddhist, Alan Clements, in Voice of Hope. Clements shared a Buddhist teacher with her and he told me that the meditational practices she is known to pursue are vital to cultivate the courage and insight for her political battles. When asked by Clements what her greatest struggle was, she replied: "It's always a matter of developing more and more awareness, not only day to day but moment to moment. It's a battle which will go on the whole of my life." Her greatest aim, she told him, was "purity of mind".

It is the awareness which enables her to perceive the fear that lies behind the violence of the Burmese junta and to insist on offering them dialogue. The practice of metta – "loving kindness" – is not passive, she says, and points to the Buddha himself, who went to stand between two warring parties to protect them both at the risk of his own safety.

This is a radical message for western politics steeped in a technocratic managerialism and obsession with presentation: that the personal spiritual struggle cannot be stripped out of politics. But perhaps what gets overlooked is how revolutionary her message also is to her own Buddhist tradition. Not only is she a woman, she is a lay woman in a faith tradition dominated by male monasticism. Across Asia, those monastic institutions have frequently become complicit in state structures – in Burma, spiritual preoccupations have often been an excuse for disengagement. In her Reith lecture she picks her words carefully. "There is certainly a danger that the acceptance of spiritual freedom as a satisfactory substitute for all other freedoms could lead to passivity and resignation.

But an inner sense of freedom can reinforce a practical drive for the more fundamental freedoms in the form of human rights and the rule of law." She points to the monks who led the 2007 saffron revolution as acting out of "loving kindness" for the people suffering from sharp rises in food prices. She is putting herself at the forefront of the reforming movements in Buddhism in Asia, gently insisting on the interrelationship between practical action and private spiritual discipline.

Lastly, Aung San Suu Kyi's Buddhism is challenging one of the most persistent orientalist myths. Just as Islam was characterised as violent by Christian imperialists, Buddhism was scorned for its quietism, and self-absorbed fatalism: both were treated with comparable contempt under colonialism. Theistic Christians found Buddhism incomprehensible. That legacy persists; the current pope has described Buddhism as "self-indulgent eroticism". Bizarrely, Buddha statuary end up as a staple of garden centres, the Buddha as the consumer's symbol of calm and detachment. In a television interview the Beckhams once appeared in their sitting room alongside a near-lifesize gilt Buddha. The popular perception is of Buddhism as a form of calming therapy, much like a massage oil.

That is to emasculate the force of a powerful philosophy with radical political implications. Aung San Suu Kyi knows all too well how Buddhism has played a major political role throughout Asia, both for good and bad. Its adherents are growing fast in both India and China, as well as in the west. Like the Dalai Lama and the Vietnamese monk Thich Nhat Hanh, she is playing a vital role in communicating through her words and her life a Buddhism that speaks to the deepest human needs.