The Obama campaign is seizing on Mitt Romney's endorsement Friday of Rep. Steve King (R-Iowa) to argue that the Republican presidential nominee is unwilling to take a stand against extreme voices among his supporters.

Romney made the endorsement during a speech in northwestern Iowa on Friday, his return to the campaign trail after a week spent preparing for the upcoming presidential debates as Democrats gathered in Charlotte.

"I'm looking here at Steve King, and he needs to be your congressman again," Romney said. "I want him as my partner in Washington."

King drew fire in May when he used a metaphor seemingly to draw a comparison between immigrants and dogs.

"You get the pick of the litter and you got yourself a pretty good bird dog," King said at a town hall meeting recorded by the liberal organization American Bridge. "Well, we've got the pick of every donor civilization on the planet."

King later defended the analogy in an interview with Fox News Latino.

“In my house, we have raised really good, high-quality Labrador Pointers; we’ve received the pick of the litter from all over the planet," King said. "You pick the vigor, the most perky."

“If someone is insulted by that, I don’t know that they belong in this country,” he continued. ”Jesus talked about animals and compared people to animals. I’m Catholic, my bishop is my shepherd and we are his sheep.”

The Obama campaign referenced the incident in a statement they circulated Friday afternoon criticizing Romney over the endorsement.

"If his speech today praising Rep. Steve King — who has questioned whether women get pregnant from rape and incest and said hateful things about immigrants — is any indication, we know he wouldn’t stand up to the most strident voices in his party," said Obama spokeswoman Lis Smith.

But a Republican aide dismissed the criticism, saying the Obama camp was trying to distract from bad headlines.

"The Obama campaign should be much more troubled about their party's convention fight over Israel, their candidate's poorly-received acceptance speech, and the disastrous jobs report today. It's no wonder their campaign is flailing," the aide said.

The Obama campaign is likely eager to turn the debate back to social issues after a disappointing August jobs report released Friday has threatened to stymie momentum from the convention in Charlotte. The economy added 96,000 jobs in August, and unemployment fell from 8.3 to 8.1 percent. But economists had expected around 150,000 jobs to be added, and the 368,000 people who dropped out of the workforce last month is the highest amount in years.