"I can go toe-to-toe with President Obama on big things," Gingrich told "There are big differences."
The former House speaker said Republican attacks on each other will pale beside the negative campaign that the Obama re-election team will unleash on the Republican nominee in the fall.
Gingrich called the request "bizarre," given Romney's refusal to release his taxes and the fact that his staff scrubbed computer records on the development of his health care plan in Massachusetts.
