This article explores how it became possible for the former Indian Prime Minister, Atal Behari Vajpayee, to make a major trust-building initiative with his Pakistani counterpart, Nawaz Sharif, at the 1999 Lahore Summit. Building on security dilemma theorizing in the field of International Relations, the present article develops the concept of a “leap of trust” as a way of understanding how decision-makers trapped in security dilemmas might break through the psychology of distrust by a frame-breaking conciliatory move. This framework is then applied to the moves that led to the development of a trusting relationship between Sharif and Vajpayee. A few months later, Pakistan launched an attack across the Line of Control (LoC) and Vajpayee felt betrayed. I explore how far Sharif knew about his army's plans to attack at Kargil and ask whether he was prisoner of a Pakistani military machine that was intent on pursuing a military solution in Kashmir irrespective of any peace process that might be developing. The article examines the lessons that Vajpayee drew from Kargil and discusses his two further attempts to recover the trust that had developed at Lahore. I conclude with an analysis of the wider lessons of this case for the success of any future leaps of trust that Indian and Pakistani leaders might take.