Republican presidential candidates Newt Gingrich, left, speaks as Mitt Romney, listens during the CBS News/National Journal foreign policy debate at the Benjamin Johnson Arena, Saturday, Nov. 12, 2011 in Spartanburg, S.C. (AP Photo/Richard Shiro)

Read more: Top 10 moments from Newt Gingrich's GOP presidential bid

Newt Gingrich officially ends his presidential campaign on Wednesday, and rumors persist that he might even endorse likely Republican nominee Mitt Romney.

On such an occasion, it should come as no surprise that President Barack Obama's campaign wants to ensure no one forgets all those nasty things Newt said out on the campaign trail about Mitt.

So on Tuesday the Obama campaign released "Newt Gingrich: Frankly, not Mitt Romney's biggest supporter," an 87-second ad that showcases Gingrich's most audacious critiques of Romney.

"Talk about low-hanging fruit," the Christian Science Monitor's Linda Feldmann wrote. "All the Obama camp needed to do was collect the most pungent of Gingrich’s attacks on Mr. Romney during primary debates and interviews, add a heavy dose of sarcasm and stir."

Despite Gingrich's documented history of zealous Romney bashing, some experts believe the former House speaker will still play an important role in the 2012 presidential election.

USA Today reported on Tuesday, "Some political analysts say Gingrich … will play (an) important role in Romney's quest for the White House. 'There are still fences to mend,' Bob Vander Plaats of the Family Leader, a group of social conservatives, (said). 'The base is very inspired to defeat Barack Obama but the base is very uninspired to elect Gov. Romney.'"

Newt Gingrich: not a big fan of Mitt Romney

The Obama campaign has a new ad out that shows clips of Newt at his contemptuous best, taking shots at Romney over issues like Bain Capitol and Swiss bank accounts.