Trump reportedly recently hired Mark Penn, a former Clinton pollster, to consult him on impeachment strategy.
According to Lockhart, the former White House press secretary under President Bill Clinton, Penn is a polarizing figure who would make the entire impeachment process even more chaotic.
"I don't expect - on Mark Penn -- as a partisan Democrat, I'm glad he's advising the president," Lockhart began.
"He's a very divisive guy, not well-liked among his peers and he will inject chaos into the process."According to Lockhart, the impeachment case against Trump is unusual, because the president has essentially admitted to the crime he is being accused of committing.
"This is an unusual case where the confession came first, the transcript. with the president admitting he did it," the former White House press secretary said, suggesting that House Democrats nevertheless must build a strong case.
"And then we just built lots of evidence to prove yes he did it, even though he confessed," he added.
Lockhart also discussed the latest impeachment polls, which appear to suggest that public support for impeachment has not changed.
"I'm not completely surprised about there being no real movement because, remember, there was a big move between late spring until the Ukraine story happened," he told CNN.
In fact, some polls suggest support for impeachment is declining. According to a Marquette University poll, for instance, a majority of voters in battleground states such as Wisconsin now opposed impeachment. Similarly, according to a new Emerson College poll, support for impeachment went down from 48 percent in October to 44 percent in November.
Republicans have suggested that the apparent shift in public opinion could change Speaker of the House of Representatives Nancy Pelosi's mind. The top Democrat could, they claim, only censure Trump, instead of allowing an impeachment vote, which would inevitably lead to a Senate trial.
House Democrats want to impeach Trump over his allegedly inappropriate contacts with the Ukrainian government. As an anonymous whistleblower alleged, Trump pressured the Ukrainians to investigate former Vice President Joe Biden, threatening to cut military aid unless his request is fulfilled.The whistleblower's allegations have been corroborated by impeachment witnesses, Democrats claim. GOP lawmakers have pushed back against the accusations, arguing that the president did nothing wrong, and complaining about procedural matters.
The White House has refused to cooperate with the investigators, defying subpoenas and stonewalling the probes.