Chris Christie, the former governor or New Jersey, said Democrats would "bring everybody they think they have to bring in," including the president's family members and close associates.
"Someone needs to defend the president of the United States here," Christie said.
Prosecutors in New York's Southern District subpoenaed documents from Trump's inauguration committee as part of a escalating investigation from its public corruption section into the president's political fundraising.
"You at the time said we are not electing an entertainer-in-chief, and then seemed to have a quick change of heart," she said.
Chris Christie was the former U.S. Attorney who prosecuted Charles Kushner for tax evasion, illegal campaign contributions and witness tampering in the early 2000s.
"I'm 56 years old. I'm not going to rule anything out. I still have a lot of life to live and a lot to contribute," Christie told Newsweek.
"It's amazing that he never let it go," Fox News host Brian Kilmeade said of Kushner's alleged grudge on Christie.
Christie claims Trump once told him to lose weight by saying, "You gotta look better to be able to win."
"Bob Mueller doesn't feel, to me, like he is almost done. I don't think he is ending on Roger Stone, but might be," Christie said on "Fox & Friends."
"I'm a big boy who understands how the way this business works. But please, sir, don't ever, ever tell me again that I wasn't fired," Christie said he told Trump.
Chris Christie wrote that Trump asked him to wear a longer tie to help him appear skinnier.
"Again, the president was ill served by poor advice," Christie wrote.
"I have asked him to no longer keep me in any of his considerations for this post," the former New Jersey governor said.
"When prosecutors sound that definitive they've got more usually than just one witness," Chris Christie said.
"This is not in the president's interest. It wasn't in the president's interest," former Governor Chris Christie said Sunday. "It's bad legal advice. Bad lawyering."
Attorney to President Donald Trump, Rudy Giuliani, continued taking shots at special counsel Robert Mueller Sunday, saying it's unlikely Trump ever sits for an interview with Mueller.
Christie described the White House counselor as "skilled on television."
Christie left the governor's mansion earlier this week with a 14 percent approval rating. Trump should take note.
President Donald Trump is "not my cup of tea," said incoming New Jersey Governor Phil Murphy.
During his last weeks as the governor of New Jersey, Chris Christie said in an interview that he would have been president if Trump hadn't run in 2016.
"Whether he deserves it or not, he's getting it," Christie said of scrutiny on Kushner.
A Morning Consult/Politico poll out Thursday showed that 45 percent of people said they thought he's doing a good job.
Governor Chris Christie said one of the reasons he was fired as the chairman of Trump's transition team was because he opposed hiring Michael Flynn.
Republican candidates lost gubernatorial elections in both states.