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Matt Rourke, Associated Press
Republican presidential candidate, former House Speaker Newt Gingrich, accompanied by his wife Callista, waits to speak at a Tea Party Rally, Thursday, Jan. 26, 2012, in Mount Dora, Fla.

As former House speaker Newt Gingrich lambasted Mitt Romney on Thursday in Florida, former GOP presidential nominee Bob Dole aired his own criticisms of Gingrich.

In a letter released by Romney's campaign, Dole wrote that he felt it was time to take a stand against Gingrich, "before it is too late."

"If Gingrich is the nominee it will have an adverse impact on Republican candidates running for county, state, and federal offices," the letter states. "Hardly anyone who served with Newt in Congress has endorsed him and that fact speaks for itself. He was a one-man-band who rarely took advice. It was his way or the highway."

Dole's letter also touches on the ethics probe against Gingrich (who was exonerated by the Internal Revenue Service) as well as Gingrich's propensity for picking fights and his desire for attention.

"Newt would show up at the campaign headquarters with an empty ice-bucket in his hand — that was a symbol of some sort for him — and I never did know what he was doing or why he was doing it," Dole writes. "In my opinion if we want to avoid an Obama landslide in November, Republicans should nominate Governor Romney as our standard bearer. He has the requisite experience in the public and private sectors. He would be a president we could have confidence in."

Read the full letter at USA Today.

In December, Dole also endorsed Romney for president in an advertisement in the Des Moines Register.

"I've known Mitt and his family for decades," Dole said in his endorsement. "His parents instilled in him a strong work ethic, rock-solid conservative values, and a deep sense of service to others. These traits — which have shone through in both the debates and my own visits with him — will serve him well in the White House."

According to the Associated Press, Gingrich has hinted he plans to attack aggressively in Thursday's Jacksonville debate.

A new Monmouth University Poll released Thursday gives Romney a 7-point lead over Gingrich among likely Republican primary voters in Florida. Tea party support for both candidates splits at 38 percent, although Gingrich does better among those who say they strongly support the tea party. These results are similar to the Times-Union/Insider Advantage survey released Wednesday that shows Romney with a 40-32 lead over Gingrich.