Andrew Harnik / AP

The most persistent lie about Obama's background began in 2004 when Andy Martin, a Illinois candidate distributed a press release — which was widely shared — saying that Obama was a Muslim who concealed his religion.

The idea that Obama was born outside the US evolved from that theory, and was then picked up by Obama's enemies — including some Clinton supporters during the 2008 campaign and Republicans after he was elected.

But neither Clinton nor any of her staff ever publicly — or even privately to reporters who covered them closely — suggested that there was a mystery around Obama's birth. The first public figures to embrace the theory were Republican members of the House of Representatives, followed by Donald Trump.