A group that backs California's marijuana-legalization initiative (Prop. 19) and other moves to decriminalize pot launched a campaign against Facebook Tuesday after the social-networking juggernaut allegedly banned its pot-leaf ads on the site.

States Just Say Now: “After our ads with the 'Just Say Now' logo of marijuana leaf ran more than 38 million times, Facebook flip-flopped and banned all images of marijuana from its ads.”

According to the Huffington Post (via LAist), Facebook sent an email to the organization stating it had a problem with its pot-leaf imagery:

Adam Noyes, a spokesman for Facebook, said that the problem was the pot leaf. “It would be fine to note that you were informed by Facebook that the image in question was no long[er] acceptable for use in Facebook ads. The image of a pot leaf is classified with all smoking products and therefore is not acceptable under our policies,” he told the group in an email, which was provided to HuffPost.

The Washington, D.C.-based Just Say Now has started a petition that asks Facebook to reverse its decision.

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