Clarke's "ideas" began taking shape when - as a civil servant before the war - he started writing tales about outer space.

BBC: Legendary science fiction writer Arthur C Clarke at 80

So, the idea of growing up to be president some day was implanted in my head, and it became the source of great consternation for me when, in grad school in the late '60s as civil rights, feminist and anti-Vietnam War ferment was swelling, I ratified my own commitment to social justice by openly claiming my gay identity.

CNN: White House is finally a welcoming place for gay people

His impeachment came when he sacked his secretary of war, in defiance of the view of the Republican-controlled Senate that civil officers could be removed only with the Senate's approval.

ECONOMIST: The misty road to impeachment