In the race for the Republican presidential nomination, Rep. Michele Bachmann just can’t seem to hold onto any momentum for long, a fate partly of her own making, according to one former top staffer.

The Minnesota congresswoman won the Iowa straw poll a month ago, only for her victory to lose some of its luster as Texas Gov. Rick Perry leapt into the presidential race and instantly surged to the front of the GOP pack. But Bachmann didn’t help herself any by joking about a deadly hurricane.

Then, this week, she stole the show at Monday’s debate in Tampa by going toe to toe with Perry: Not only did she criticize his executive order to require young girls to receive inoculations against a virus that can cause cervical cancer, but she questioned whether the mandate was made in exchange for help — financial and otherwise — from pharmaceutical giant Merck. But just like her Ames win, Bachmann’s impressive debate performance has now been overshadowed, in no small part by her own doing.

No sooner had she won praise for rejuvenating her campaign with her aggressive showing at the debate than Bachmann opened herself up to criticism by claiming that the vaccine can cause mental retardation.

“I had a mother last night come up to me here in Tampa, Florida, after the debate,” Bachmann told NBC’s “Today Show” Tuesday morning. “She told me that her little daughter took that vaccine, that injection, and she suffered from mental retardation thereafter.”

The pushback to that claim — that the vaccine can cause retardation — came hard and fast. Perry Wednesday said Bachmann’s statement had “no truth and no basis in fact,” although such criticism was to be expected from the rival on the receiving end of the statements. What really hurt Bachmann’s case were the responses that came from outside the GOP race, even from her former campaign manager, no less.

Ed Rollins, who up until Labor Day weekend was running Bachmann’s campaign, told NBC’s “Hardball” that “she’d have been better if she stayed on issue.”

“The quicker she admits she made a mistake, the better,” Rollins said.

The pushback didn’t stop there either. The American Academy of Pediatrics issued a statement denouncing Bachmann’s suggestions.

“The American Academy of Pediatrics would like to correct false statements made in the Republican presidential campaign that HPV vaccine is dangerous and can cause mental retardation,” it said. “There is absolutely no scientific validity to this statement.”

Bioethicist Art Caplan of the University of Pennsylvania  said he would donate $10,000 to the charity of Bachmann’s choice if she can produce a patient who was left mentally retarded by injections of the Gardasil vaccine.

For her part, Bachmann later said she was merely “reporting what this woman was reporting last night at the debate,” as she told Chris Matthews on “Hardball.”

But it was Bachmann who called attention to that woman’s unverified statements, relaying them to a national audience as if they were fact. For a candidate who already has a reputation for gaffes, such comments are nothing new and, therefore, could prove all the more harmful.

She joked last month that Hurricane Irene, a storm that left more than 30 people dead along the East Coast , was God’s way of sending a message to Washington politicians to cut back on federal spending. And  she made a blunder earlier this year by saying that the Revolutionary War battle at Lexington and Concord had taken place in New Hampshire, when it happened in Massachusetts.

Bachmann sat down for dinner Tuesday evening with Cindy McCain at a Mexican restaurant in Phoenix. If Bachmann is to follow in the footsteps of McCain’s husband, John, and win the Republican nomination for president, then she will have to put to rest questions about her loose lips.

Unfortunately for Bachmann’s campaign, the best place to do that might not be a nationally televised appearance on a late-night comedy show. But that’s exactly what awaits her Friday night when she takes the stage in Los Angeles for an appearance on “The Tonight Show.”