Mercede Johnston Ups Feud With Sarah, Bristol Palin 2Mercede Johnston, soon-to-be Playmate and sister of Bristol Palin’s baby daddy Levi Johnston, slammed family matriarch Sarah Palin, calling her too mentally unstable to be president.

Palin, the 2008 Republican Vice Presidential candidate with John McCain, has been an outspoken right-wing conservative since losing the election, and has been widely mentioned as a possible 2012 presidential contender.

The Palin’s and Johnston’s used to be close when Bristol was engaged to Levi Johnston. But after their break up, the two families have had a falling out.

In the latest blast, Johnston, 18, charges that Palin would have a “mental breakdown” if she were ever elected president.

“I think she’d have had a mental breakdown… As governor she quit on us. What does that say about her?,” she says in her Playboy interview, according to the New York Post.

Johnston said “70 percent” of residents in Palin’s hometown have a negative impression of the former Alaska governor.

She essentially said the Palin household is dysfunction. Bristol’s brother Track, 22, was forced to join the Army to keep him out of the spotlight after McCain chose Palin as his vice presidential running mate.

“His mom made him,’ Mercede said. She wanted him ‘out of the way so when she was at the convention they wouldn’t know he does drugs and would think he was a patriot.”

In Palin’s hometown, unemployment is high and opportunities are lacking and drug use is rampant. Track was into
“OxyContin and mostly cocaine,” she said.

Mercede and Levi’s mother, Sherry Johnston, was convicted in 2009 of dealing OxyContin and is a serving three-year sentence under house arrest.

Track married high school sweetheart Britta Hanson in May and she gave birth over the weekend to their first child Kayla Grace on Saturday.

Bristol was an 18-year-old unwed mother when she gave birth to her boy Tripp in 2008.