SARAH PALIN knew that if she wanted to make a serious run for the Presidency in 2012 she’d have take care of  "The Levi Problem" once and for all. 

So she hatched a plan to discredit him publicly – and then get rid of him!

That’s the REAL story behind the quickie "makeup ‘n’ breakup" between her daughter Bristol, 19, and baby daddy Levi Johnston, 20, a source told The ENQUIRER.

Last year, Levi publicly ripped into Sarah and the Palins, revealing embarrassing details about their family and home life.

"Sarah threw a fit," said the source.

To have a chance to be president, Sarah knew that she’d have to figure out a way to stop Levi from further sullying her reputation.

"So Sarah hatched a plan to discredit him," divulged the source.

First, she encouraged Bristol to let Levi spend more time with their 20-month-old son, Tripp.

"Then, when Levi started to have feelings for Bristol again, Sarah talked to him about how he had embarrassed their family," said the source.

In June, Sarah told Levi it was time for him to publicly retract the embarrassing statements he had made, says the source.

"At first he resisted, but Bristol convinced him that it was going to be for the best if he ever wanted to be back in their family."

In early July, Sarah got what she wanted. Levi released a statement saying the things he said about the Palins were "not completely true," and he chalked it up to  "youthful indiscretion."

"Her mission was accomplished, because now, no matter what Levi said about the Palins in the future, nobody would believe him," said the source.

"Her plan worked – Levi was branded a liar by his own words."

But Sarah’s plan almost backfired when Bristol and Levi announced a week later that they were engaged!

"The news hit Sarah like a ton of bricks," said the source.

Fortunately for the former Alaskan governor, the reconciliation was short-lived. Right after making their engagement public, Levi confessed to Bristol that he may have fathered a baby with another young woman.

The ENQUIRER exclusively revealed the pregnancy of Lanesia Garcia – an ex-girlfriend of Levi’s – in our Aug. 9 issue. Lanesia has since denied that Levi is the father.  But after Sarah heard about the pregnancy, she persuaded a distraught Bristol to call off the engagement.

Levi wasted no time jumping back into the limelight announcing a new reality show and running for Sarah’s old mayoral gig in Wasilla, Alaska.

Aside from her daughter’s broken heart, Sarah couldn’t be more pleased with how she accomplished her plan, the source divulged.