Video recently posted to Instagram appears to show Ms Obama blowing smoke rings in a bathroom. The caption on the video identified the former first daughter by name and claimed she was “firing off them O’s like a boss”.
After conservative news site The Daily Caller wrote an article about the video, Ms Trump came forward to defend her.
“Malia Obama should be allowed the same privacy as her school aged peers,” the first daughter and presidential adviser tweeted. “She is a young adult and private citizen, and should be OFF limits.”
Ms Trump was joined by another former first daughter, Chelsea Clinton, who tweeted: “Malia Obama’s private life, as a young woman, a college student, a private citizen, should not be your clickbait. Be better.”
In fact, the scrutiny of Ms Obama seemed unpopular on many corners of the internet. Former ESPN host and occasional Trump defender Britt McHenry tweeted that it was “not a partisan thing” to defend the former first daughter's privacy.
Right-wing figures such as Turning Point USA founder Charlie Kirk and blogger Mike Cernovich both urged their followers to leave the 19-year-old alone.
“Malia Obama isn’t throwing shade or doing anything public, no reason to act as if she’s in this game. Civilian,” Mr Cernovich tweeted. “Leave her alone!”
On the left, several commentators tweeted that they were impressed by the teenagers smoke-ring-blowing skills. Still others compared Ms Obama’s actions to the alleged behaviour of the Trump children.
“When Malia Obama cuts off an elephant's tail and sells our country out to the Russians call me,” tweeted filmmaker Jeremy Newberger.
Ms Obama has been somewhat of a media fascination since she turned 18. Photos of her smoking at last year's Lollapalooza music festival sparked speculation as to what she could be inhaling. An evening stroll with platonic friend Rob Franklin earlier this year caused gossip website TMZ to wonder who her “mystery man” could be.
The rumour mill sparked up again just last week, when Ms Obama was seen kissing someone at a Harvard football game against Yale. He has since been identified as 19-year-old Rory Farquharson, a UK native and fellow Harvard student.
Barack Obama has not spoken publicly about his eldest daughter's behaviour, but did tell reporters that dropping her off at college nearly broke his heart.
"I was saying to Joe and Jill (Biden) that it was a little bit like open-heart surgery, and I was proud that I did not cry in front of her," he said. "But on the way back, the Secret Service was off, looking straight ahead, pretending they weren't hearing me as I sniffled and blew my nose. It was rough."
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