Ipso facto -- by the fact itself

(from www.wordsmith.org)

ipso facto (IP-so FAK-to) adverb
By the very fact or action. [Latin ipso facto (by the fact itself).]
The counterpart of this term is ipso jure, which means by reason of a particular law.

"'Spiritually, I'm a New Yorker,' [Norman Mailer] said. 'If you grow up in Brooklyn, you're a New Yorker ipso facto.'"
-- Colin Miner; Mailer on Bush, Obama & Writing; The Sun (New York); Jan 22, 2007.

Some 70s TV viewers might recall Archie Bunker's malapropist rendition of the expression above, "Ipso fatso..."