JACKSONVILLE—Preparing for a key debate in Jacksonville Thursday night, former Massachusetts governor Mitt Romney suggested to a crowd outside a closing printing plant in this economically hard-hit city that rival Newt Gingrich is too embedded in Washington culture to be the party’s nominee.

View Photo Gallery: The Republican presidential debate in Tampa was the the 17th such showdown to date, and the first since former House speaker Newt Gingrich’s (R-Ga.) come-from-behind win Saturday in South Carolina.

But his reference to Gingrich was brief and in passing, a stark contrast with his chief rival for the Republican nomination, who opened up on Romney at an earlier event Thursday. In a harsh and personal attack at a tea party gathering in Mount Dora, the former House speaker called Romney’s campaign “grotesquely hypocritical” and mocked his investments in Swiss bank accounts and offshore in the Cayman Islands.

Romney reserved most of his attacks at an economic address to a crowd of about 100 for President Obama.

“We’re getting ready for another debate--I can’t wait,” Romney said, indicating the debate may focus largely on Obama. But, he added, “We may talk about the differences between ourselves as well. There may be some give and take. That’s always fun and entertaining.”

He continued: “Florida’s going to make a decision about who we want to be our nominee. And I’ve got something to admit. I’ve never lived in Washington, D.C. I’m not part of the culture of Washington, DC…. If you think you need someone who’s been a part of the culture of Washington for the last 35 years to go there again and continue in Washington, there are other people you can choose.”

The mild tone on Gingrich is a gamble on Romney’s part, as voters who handed Gingrich in big win in South Carolina said one thing they liked about him was his fighting spirit. But it could be a calculated gamble, that Florida voters will sour on what they could see as Gingrich’s bombast. Meanwhile, Florida airwaves are being flooded with negative ads about Gingrich funded by a pro-Romney political action committee.