However, Milk's assassination has become entwined with his political efficacy, partly because he was killed at the zenith of his popularity. Historian Neil Miller writes, "No contemporary American gay leader has yet to achieve in life the stature Milk found in death." His legacy has become ambiguous; Randy Shilts concludes his biography writing that Milk's success, murder, and the inevitable injustice of White's verdict represented the experience of all gays. Milk's life was "a metaphor for the homosexual experience in America". According to Frances FitzGerald, Milk's legend has been unable to be sustained as no one appeared able to take his place in the years after his death: "The Castro saw him as a martyr but understood his martyrdom as an end rather than a beginning. He had died, and with him a great deal of the Castro's optimism, idealism, and ambition seemed to die as well. The Castro could find no one to take his place in its affections, and possibly wanted no one." On the 20th anniversary of Milk's death, historian John D'Emilio said, "The legacy that I think he would want to be remembered for is the imperative to live one's life at all times with integrity." For a political career so short, Cleve Jones attributes more to his assassination than his life: "His murder and the response to it made permanent and unquestionable the full participation of gay and lesbian people in the political process."