There is a long history of bad blood between Gingrich and Coburn, who served in the House when the former was speaker. Here are excerpts from Coburn's 2003 book, Breach of Trust:
In an interview on ABC’s "Subway Series" with Jonathan Karl to be released Friday morning , Senator Tom Coburn says Gingrich needs “keep his mouth shut” about Paul Ryan’s Medicare plan until he has his own plan to deal with skyrocketing entitlement spending... “You know, he used to have a little deal in his office that said listen, learn, help and lead. And he rarely followed it. He went the other way. And instead of ready, aim, fire, you got a fire, ready, aim,” Coburn said. “I think it’s unfortunate for him and unfortunate for the country.”
- "Before the government shutdown we thought Newt Gingrich was invincible. After the shutdown, however, he was like a whipped dog, who still barked, yet cowered, in Clinton's presence. Our policies after the shutdown were inconsistent, and Gingrich's leadership seemed erratic. He would often surprise and shock us with his midstream course corrections, as he did with his attempt to increase committee funding. His inability to discipline himself in his public comments was also a serious liability" (pp. 80-81).
- Coburn took part in an unsuccessful 1997 effort to remove Gingrich from the speakership. He regretted the failure. "For example, the next year Gingrich would secure $450 million for the construction of seven C-130J transport planes in his district, though the Pentagon ordered only one. As he secured one of the largest pork projects in history, Republicans lost seats. This was the type of thing we were raging against..." (p. 89)
- After that seat loss, Gingrich left Congress. "The day Newt Gingrich resigned, he hosted a conference call in which he bitterly blasted the `cannibals' in the Republican party for his demise. The call was somber and very sad. The vast majority of Republicans by this point, not just the conservative `cannibals,' had come to see Gingrich as a tragic figure who, through his own missteps and errors in judgement, had become more of a liability than an asset, in spite of his enormous gifts" (p. 138).