While Manning was in prison, the Defence Department last year lifted a long-standing ban against transgender men and women serving openly in the military. This freed 7000 active and reserve transgender members to tell the truth about their gender identity, according to Pentagon estimates.
Although transgender people still complain of discrimination in education, employment and medical care, awareness of the issue has exploded since Manning went to jail.
Manning, 29, is likely to become a transgender advocate after her release from the US Disciplinary Barracks at Fort Leavenworth, Kansas, said Chase Strangio, a lawyer with the American Civil Liberties Union who has represented Manning.
"She is someone who is driven by a sense of justice. And I don't see her fading into a private life," Strangio said, listing transgender youth, prisoners and women of colour as potential causes.
Still, Manning faces a difficult transition to freedom, Strangio said. Social conservatives reject expansion of transgender rights, and many national security experts revile her for providing more than 700,000 documents, videos, diplomatic cables and battlefield accounts to WikiLeaks while serving as an intelligence analyst in Baghdad.
Manning said she disclosed classified information "out of a love for my country" to expose truths about the civil war in Iraq.
At the same time, the reputation of WikiLeaks has declined as part of the ebb and flow of public perceptions of national security, said Robert Deitz, who previously served as general counsel at the National Security Agency, senior councillor to the director of the CIA, and other national security positions. "Public perception of intel changes according to what's going on in the world," Deitz said, adding that he felt Manning should have served the full 35 years. "She did enormous damage to the intelligence community."