President Donald Trump's lawyer, Rudy Giuliani, substantially weakened his case against Michael Cohen by going back and forth as to whether Cohen could tell federal prosecutors the truth, said Jay Goldberg, President Donald Trump's friend and former lawyer.
Giuliani called Cohen, Trump's former personal lawyer, "honorable" and truthful on several occasions before an audio recording of a discussion between Cohen and Trump about buying rights to a Playboy model's story about an alleged affair Trump took part in became publicized.
After CNN aired the audio, Giuliani called Cohen a "pathological liar" and said he doesn't "see how he has any credibility."
"I expected something like this from Cohen," Giuliani told CNN's Chris Cuomo on Thursday. "He's been lying all week. He's been lying for years."
Goldberg, who served as Trump's divorce lawyer for the President's first two marriages, said Giuliani "immeasurably" damaged his case against Cohen by changing his tune.
"I knew as soon as Giuliani spoke that he was damaging Trump's case immeasurably," Goldberg told CNN's "Erin Burnett Out Front." "It ranks near 100 in terms of damage."
"No defense lawyer would say that," Goldberg later added.
Goldberg argued that Giuliani's early assertion on ABC's "This Week with George Stephanopoulos" that Cohen would tell federal prosecutors the truth "strips the defense of its main weapon of claiming that he is coloring his testimony to favor the government, so he can get a letter of cooperation."
The former Trump lawyer also said that he advised the President not to hire Giuliani.
"I didn't think Giuliani knew how to handle a case from the defense perspective. He was a long-time prosecutor and he didn't know how to set a case up for the possible impeachment of a witness such as Cohen," Goldberg said.