Cory Booker, the Democratic mayor of Newark, N.J., who said Sunday political language used on both sides of the aisle is "nauseating," dialed back his comments on Monday, saying in an interview that the rhetoric of his own party is far milder than language used by Republicans.

Booker said that GOP presidential candidate Mitt Romney's experience leading the private equity firm Bain Capital should be on the table, after saying on Sunday that he was not going "to sit here and indict private equity." Republicans seized upon that remark, on NBC's "Meet The Press," which Booker later walked back in a YouTube video, as one of the President Barack Obama's supporters calling out "ridiculous" rhetoric in his own ranks.

"If anything they've turned me on," Booker said of the backlash from Republicans in a Monday appearance on MSNBC.

Republican criticism of Obama involving his one-time spiritual mentor, Rev. Jeremiah Wright, "can't even be equated" with the comparatively mild language used by Democrats, he said in the interview.

On Sunday, Booker invoked the Bain and Wright attacks as examples of discussions that are distracting from the larger issues facing the U.S.

But on Monday, Booker was clear that Bain, and Romney's business record overall, are very much fair game.

He drew a distinction between Romney's claim that his investments produced jobs, rather than only returns for his investors.

"When he says he was a job creator, I think that's a characterization of his record that deserves inquiry," Booker said.

Asked about his supporter's comments at a Monday news conference, Obama said Bain should be in play.

"When you're president, as opposed to the head of a private equity firm, then your job is not simply to maximize profits. Your job is to figure out how everybody in the country has a fair shot," Obama said.

However, Booker was not clear where the line should be drawn between the "appropriate questions" about Romney's record that he referenced Monday, and the "ridiculous" that he mentioned Sunday.

Booker said he felt "used" by the Republican National Committee, which highlighted the remarks in an email to supporters, and said that a Sunday afternoon response he made on YouTube after the comments went viral was not at the request of the Obama campaign.