Sales of pocket versions of the US Constitution have soared since the father of a fallen Muslim American soldier brandished a copy to denounce Donald Trump, igniting a major backlash against the Republican nominee.

Khizr Khan, a Harvard-educated lawyer whose son died in a 2004 suicide bombing in Iraq, went head to head with the insult-dishing White House candidate in a confrontation that has dominated the US news cycle for days.

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On Amazon's best seller list, a pocket edition of the US constitution is second only to the new "Harry Potter and the Cursed Child" script, and number one best seller in Amazon's US history category.

The 52-page paperback, on sale for $1 on Amazon, does not appear to be the same edition that Khan whipped out of his pocket in one of the most defining moments of last week's Democratic National Convention.

Publishers of another volume, "The US Constitution and Fascinating Facts About It," told AFP they had completely sold out and seen nothing like it in 23 years of operations.

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